Name: preparation of biomass-based mesoporous carbon with higher nitrogen-/oxygen-chelating adsorption for cu(ii) through microwave pre-pyrolysis
Uploaded: 2019-02-12T12:30:00
Description: Watch this Scientific Journal Video about Preparation of Biomass-based Mesoporous Carbon with Higher Nitrogen-/Oxygen-chelating Adsorption for CuII Through Microwave Pre-Pyrolysis at JoVE.com

The authors acknowledge the Fundamental Research Funds for the Central Universities of China (No.KYZ201562), China Postdoctoral Science Fund (No. 2014M560429) and the Key research and development plan of Jiangsu Province (No. BE2018708).

1. Preparation of Bagasse-based Activated Carbon
<ol>
	<li>Preparation of the precursor for bagasse-based activated carbon
	<ol>
		<li>Rinse the bagasse (obtained from a farm in Jiangsu, China) with deionized water and put the samples in a drying oven at 100 &#176;C for 10&#160;h.</li>
		<li>Crush the dried bagasse with a grinder and sieve the powder through a 50-mesh sieve.</li>
		<li>Place 30 g of fine bagasse powder into a 15 wt% phosphoric acid (H3PO4) solution in a 1:1 weight...

<ol>
	<li>Saleh, T. A., Gupta, V. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Processing+methods,+characteristics+and+adsorption+behavior+of+tire+derived+carbons:+a+review.">Processing methods, characteristics and adsorption behavior of tire derived carbons: a review.</a> Advances in Colloid &amp; Interface Science. 211, 93 (2014).</li><li>Mohammadi, N., Khani, H., Gupta, V. K., Amereh, E., Agarwal, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Adsorption+process+of+methyl+orange+dye+onto+mesoporous+carbon+material-kinetic+and+thermodynamic+studies.">Adsorption process of methyl orange dye onto mesoporous carbon material-kinetic and thermodynamic studies.</a> Journal of Colloid &amp; Interface Science. 362 (2), 457 (2011).</li><li>Saleh, T. A., Gupta, V. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Column+with+CNT/magnesium+oxide+composite+for+lead(II)+removal+from+water.">Column with CNT/magnesium oxide composite for lead(II) removal from water.</a> Environmental Science &amp; Pollution Research. 19 (4), 1224-1228 (2012).</li><li>Asfaram, A., Ghaedi, M., Agarwal, S., Tyagi, I., Kumargupta, V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Removal+of+basic+dye+Auramine-O+by+ZnS:Cu+nanoparticles+loaded+on+activated+carbon:+optimization+of+parameters+using+response+surface+methodology+with+central+composite+design.">Removal of basic dye Auramine-O by ZnS:Cu nanoparticles loaded on activated carbon: optimization of parameters using response surface methodology with central composite design.</a> RSC Advances. 5 (24), 18438-18450 (2015).</li><li>Gupta, V. K., Saleh, T. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Sorption+of+pollutants+by+porous+carbon,+carbon+nanotubes+and+fullerene-+an+overview.">Sorption of pollutants by porous carbon, carbon nanotubes and fullerene- an overview.</a> Environmental Science and Pollution Research. 20 (5), 2828-2843 (2013).</li><li>Ahmaruzzaman, M., Gupta, V. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Rice+Husk+and+Its+Ash+as+Low-Cost+Adsorbents+in+Water+and+Wastewater+Treatment.">Rice Husk and Its Ash as Low-Cost Adsorbents in Water and Wastewater Treatment.</a> Industrial &amp; Engineering Chemistry Research. 50 (24), 13589-13613 (2011).</li><li>Ahmed, M. J., Theydan, S. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Adsorption+of+cephalexin+onto+activated+carbons+from+Albizia+lebbeck+seed+pods+by+microwave-induced+KOH+and+K2CO3+activations.">Adsorption of cephalexin onto activated carbons from Albizia lebbeck seed pods by microwave-induced KOH and K2CO3 activations.</a> Chemical Engineering Journal. 211 (22), 200-207 (2012).</li><li>Liew, R. K., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Production+of+activated+carbon+as+catalyst+support+by+microwave+pyrolysis+of+palm+kernel+shell:+a+comparative+study+of+chemical+versus+physical+activation.">Production of activated carbon as catalyst support by microwave pyrolysis of palm kernel shell: a comparative study of chemical versus physical activation.</a> Research on Chemical Intermediates. , 1-17 (2018).</li><li>Lam, S. S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Microwave-assisted+pyrolysis+with+chemical+activation,+an+innovative+method+to+convert+orange+peel+into+activated+carbon+with+improved+properties+as+dye+adsorbent.">Microwave-assisted pyrolysis with chemical activation, an innovative method to convert orange peel into activated carbon with improved properties as dye adsorbent.</a> Journal of Cleaner Production. 162, 1376-1387 (2017).</li><li>Jin, H., Wang, X., Gu, Z., Polin, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Carbon+materials+from+high+ash+biochar+for+supercapacitor+and+improvement+of+capacitance+with+HNO3+surface+oxidation.">Carbon materials from high ash biochar for supercapacitor and improvement of capacitance with HNO3 surface oxidation.</a> Journal of Power Sources. 236, 285-292 (2013).</li><li>Chen, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Research+Methods+for+the+Biotechnology+of+Lignocellulose.">Research Methods for the Biotechnology of Lignocellulose.</a> Biotechnology of Lignocellulose: Theory and Practice. , 403-510 (2014).</li><li>Say&#287;&#305;l&#305;, H., G&#252;zel, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=High+surface+area+mesoporous+activated+carbon+from+tomato+processing+solid+waste+by+zinc+chloride+activation:+process+optimization,+characterization+and+dyes+adsorption.">High surface area mesoporous activated carbon from tomato processing solid waste by zinc chloride activation: process optimization, characterization and dyes adsorption.</a> Journal of Cleaner Production. 113, 995-1004 (2016).</li><li>Cao, Q., Xie, K. C., Lv, Y. K., Bao, W. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Process+effects+on+activated+carbon+with+large+specific+surface+area+from+corn+cob.">Process effects on activated carbon with large specific surface area from corn cob.</a> Bioresource Technology. 97 (1), 110-115 (2006).</li><li>Xiao, X., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Adsorption+behavior+of+phenanthrene+onto+coal-based+activated+carbon+prepared+by+microwave+activation.">Adsorption behavior of phenanthrene onto coal-based activated carbon prepared by microwave activation.</a> Korean Journal of Chemical Engineering. 32 (6), 1129-1136 (2015).</li><li>Ge, X., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Adsorption+of+naphthalene+from+aqueous+solution+on+coal-based+activated+carbon+modified+by+microwave+induction:+Microwave+power+effects.">Adsorption of naphthalene from aqueous solution on coal-based activated carbon modified by microwave induction: Microwave power effects.</a> Chemical Engineering &amp; Processing Process Intensification. 91, 67-77 (2015).</li><li>Yao, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Removal+of+Pb(II)+from+water+by+the+activated+carbon+modified+by+nitric+acid+under+microwave+heating.">Removal of Pb(II) from water by the activated carbon modified by nitric acid under microwave heating.</a> Journal of Colloid and Interface Science. 463, 118-127 (2016).</li><li>Ali, A., Idris, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Utilization+Of+Low-cost+Activated+Carbon+From+Rapid+Synthesis+Of+Microwave+Pyrolysis+For+WC+Nanoparticles+Preparation.">Utilization Of Low-cost Activated Carbon From Rapid Synthesis Of Microwave Pyrolysis For WC Nanoparticles Preparation.</a> Advanced Materials Letters. 08 (1), 70-76 (2016).</li><li>Puchana-Rosero, M. J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Microwave-assisted+activated+carbon+obtained+from+the+sludge+of+tannery-treatment+effluent+plant+for+removal+of+leather+dyes.">Microwave-assisted activated carbon obtained from the sludge of tannery-treatment effluent plant for removal of leather dyes.</a> Colloids and Surfaces A: Physicochemical and Engineering Aspects. 504, 105-115 (2016).</li><li>Du, Z. L., Zheng, T., Wang, P., Hao, L. L., Wang, Y. X. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fast+microwave-assisted+preparation+of+a+low-cost+and+recyclable+carboxyl+modified+lignocellulose-biomass+jute+fiber+for+enhanced+heavy+metal+removal+from+water.">Fast microwave-assisted preparation of a low-cost and recyclable carboxyl modified lignocellulose-biomass jute fiber for enhanced heavy metal removal from water.</a> Bioresource Technology. 201, 41-49 (2016).</li><li>Ge, X., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Microwave-assisted+modification+of+activated+carbon+with+ammonia+for+efficient+pyrene+adsorption.">Microwave-assisted modification of activated carbon with ammonia for efficient pyrene adsorption.</a> Journal of Industrial &amp; Engineering Chemistry. 39, 27-36 (2016).</li><li>Ghaedi, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Modeling+of+competitive+ultrasonic+assisted+removal+of+the+dyes+-+Methylene+blue+and+Safranin-O+using+Fe3O4+nanoparticles.">Modeling of competitive ultrasonic assisted removal of the dyes - Methylene blue and Safranin-O using Fe3O4 nanoparticles.</a> Chemical Engineering Journal. 268, 28-37 (2015).</li><li>Gupta, V. K., Nayak, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cadmium+removal+and+recovery+from+aqueous+solutions+by+novel+adsorbents+prepared+from+orange+peel+and+Fe2O3+nanoparticles.">Cadmium removal and recovery from aqueous solutions by novel adsorbents prepared from orange peel and Fe2O3 nanoparticles.</a> Chemical Engineering Journal. 180 (3), 81-90 (2012).</li><li>Robati, D., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Removal+of+hazardous+dyes-BR+12+and+methyl+orange+using+graphene+oxide+as+an+adsorbent+from+aqueous+phase.">Removal of hazardous dyes-BR 12 and methyl orange using graphene oxide as an adsorbent from aqueous phase.</a> Chemical Engineering Journal. 284 (7), 687-697 (2016).</li><li>Ali, I., Alothman, Z. A., Sanagi, M. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Green+Synthesis+of+Iron+Nano-Impregnated+Adsorbent+for+Fast+Removal+of+Fluoride+from+Water.">Green Synthesis of Iron Nano-Impregnated Adsorbent for Fast Removal of Fluoride from Water.</a> Journal of Molecular Liquids. 211, 457-465 (2015).</li><li>Gupta, V. K., Kumar, R., Nayak, A., Saleh, T. A., Barakat, M. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Adsorptive+removal+of+dyes+from+aqueous+solution+onto+carbon+nanotubes:+A+review.">Adsorptive removal of dyes from aqueous solution onto carbon nanotubes: A review.</a> Advances in Colloid &amp; Interface Science. 193 (6), 24 (2013).</li><li>Mittal, A., Mittal, J., Malviya, A., Gupta, V. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Adsorptive+removal+of+hazardous+anionic+dye+&amp;#34;Congo+red&amp;#34;+from+wastewater+using+waste+materials+and+recovery+by+desorption.">Adsorptive removal of hazardous anionic dye &amp;#34;Congo red&amp;#34; from wastewater using waste materials and recovery by desorption.</a> Journal of Colloid and Interface Science. 340 (1), 16-26 (2009).</li><li>Wan, Z., Li, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effect+of+pre-pyrolysis+mode+on+simultaneous+introduction+of+nitrogen/oxygen-containing+functional+groups+into+the+structure+of+bagasse-based+mesoporous+carbon+and+its+influence+on+Cu(II)+adsorption.">Effect of pre-pyrolysis mode on simultaneous introduction of nitrogen/oxygen-containing functional groups into the structure of bagasse-based mesoporous carbon and its influence on Cu(II) adsorption.</a> Chemosphere. 194, 370-380 (2018).</li><li>Li, K., Li, J., Lu, M., Li, H., Wang, X. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Preparation+and+amino+modification+of+mesoporous+carbon+from+bagasse+via+microwave+activation+and+ethylenediamine+polymerization+for+Pb(II)+adsorption.">Preparation and amino modification of mesoporous carbon from bagasse via microwave activation and ethylenediamine polymerization for Pb(II) adsorption.</a> Desalination and Water Treatment. 57 (50), 24004-24018 (2016).</li><li>Yantasee, W., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Electrophilic+Aromatic+Substitutions+of+Amine+and+Sulfonate+onto+Fine-Grained+Activated+Carbon+for+Aqueous-Phase+Metal+Ion+Removal.">Electrophilic Aromatic Substitutions of Amine and Sulfonate onto Fine-Grained Activated Carbon for Aqueous-Phase Metal Ion Removal.</a> Separation Science and Technology. 39 (14), 3263-3279 (2004).</li><li>Li, Y. B., Li, K. Q., Wang, X. H., Li, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ethylenediamine+Modification+of+Hierarchical+Mesoporous+Carbon+for+the+Effective+Removal+of+Pb+(II)+and+Related+Influencing+Factors.">Ethylenediamine Modification of Hierarchical Mesoporous Carbon for the Effective Removal of Pb (II) and Related Influencing Factors.</a> International Journal of Material Science. 6 (1), 58-65 (2016).</li><li>Georgakopoulos, E., Santos, R. M., Chiang, Y. W., Manovic, V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Two-way+Valorization+of+Blast+Furnace+Slag:+Synthesis+of+Precipitated+Calcium+Carbonate+and+Zeolitic+Heavy+Metal+Adsorbent.">Two-way Valorization of Blast Furnace Slag: Synthesis of Precipitated Calcium Carbonate and Zeolitic Heavy Metal Adsorbent.</a> Journal of Visualized Experiments. (120), e55062 (2017).</li><li>Loganathan, P., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Modelling+equilibrium+adsorption+of+single,+binary,+and+ternary+combinations+of+Cu,+Pb,+and+Zn+onto+granular+activated+carbon.">Modelling equilibrium adsorption of single, binary, and ternary combinations of Cu, Pb, and Zn onto granular activated carbon.</a> Environmental Science &amp; Pollution Research. (15), 1-12 (2018).</li><li>Vunain, E., Kenneth, D., Biswick, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Synthesis+and+characterization+of+low-cost+activated+carbon+prepared+from+Malawian+baobab+fruit+shells+by+H3PO4+activation+for+removal+of+Cu(II)+ions:+equilibrium+and+kinetics+studies.">Synthesis and characterization of low-cost activated carbon prepared from Malawian baobab fruit shells by H3PO4 activation for removal of Cu(II) ions: equilibrium and kinetics studies.</a> Applied Water Science. 7 (8), 4301-4319 (2017).</li><li>Bohli, T., Ouederni, A., Villaescusa, I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Simultaneous+adsorption+behavior+of+heavy+metals+onto+microporous+olive+stones+activated+carbon:+analysis+of+metal+interactions.">Simultaneous adsorption behavior of heavy metals onto microporous olive stones activated carbon: analysis of metal interactions.</a> Euro-Mediterranean Journal for Environmental Integration. 2 (1), 19 (2017).</li><li>Bouhamed, F., Elouear, Z., Bouzid, J., Ouddane, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Multi-component+adsorption+of+copper,+nickel+and+zinc+from+aqueous+solutions+onto+activated+carbon+prepared+from+date+stones.">Multi-component adsorption of copper, nickel and zinc from aqueous solutions onto activated carbon prepared from date stones.</a> Environmental Science &amp; Pollution Research. 23 (16), 1-6 (2016).</li><li>Wu, L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Surface+modification+of+phosphoric+acid+activated+carbon+by+using+non-thermal+plasma+for+enhancement+of+Cu(II)+adsorption+from+aqueous+solutions.">Surface modification of phosphoric acid activated carbon by using non-thermal plasma for enhancement of Cu(II) adsorption from aqueous solutions.</a> Separation &amp; Purification Technology. 197, (2018).</li></ol>

In this protocol, one of the critical steps is the successful preparation of mesoporous carbon with better physicochemical properties by the one-step approach, where optimal experimental conditions need to be determined. So, in a previous study28, we have carried out orthogonal array microwave pyrolysis experiments, considering the effect of the impregnation ratio of bagasse and phosphoric acid, pyrolysis time, microwave oven power, and drying time. Besides, great care must be taken in tedious Cu(...

Activated carbon has unique adsorption properties, such as a developed porous structure, a high specific surface area, and various surface functional groups; therefore, it is employed as an adsorbent in water treatment or purification1,2,3,4. Besides its physical advantages, activated carbon is cost-effective and harmless to the environment, and its raw material (e.g., biomass) is abundant and easily obtained5,6. The physicochemical properties of activated carbon depend on the precursors that are used in its preparation and on the experimental conditions of the activation process7.
Two methods are typically used to prepare activated carbon: a one-step and a two-step approach8. The term one-step approach refers to precursors being carbonized and activated simultaneously while the two-step approach refers to that sequentially. In view of energy conservation and environmental protection, the one-step approach is more preferred for its lower temperature and pressure demanding.
Besides, chemical and physical activation are utilized to improve the textural properties of activated carbon. Chemical activation possesses apparent advantages over physical activation because of its lower activation temperature, shorter activation time, higher carbon yield, and more developed and controllable pore structure in a certain degree9. It has been tested that chemical activation can be performed by impregnating biomass used as feedstock with H3PO4, ZnCl2, or other specific chemicals, followed by pyrolysis to increase the porosity of the activated carbon, because lignocellulosic components of biomass can be easily removed by a subsequent heating treatment, owing to the dehydrogenation capability of these chemicals10,11. Hence, chemical activation greatly enhances the formation of activated carbon&#39;s pores or improves the adsorptive performance to contaminants12. An acidic activator is preferred to H3PO4, due to its relatively lower energy demand, higher yield, and less impact on the environment13.
Microwave pyrolysis has the superiority in time savings, uniform interior heating, energy-efficiency, and selective heating, making it an alternative heating method to synthesis-activated carbon14,15. Compared with conventional electric heating, microwave pyrolysis can enhance thermo-chemical processes and promote certain chemical reactions16. Recently, extensive studies have focused on preparing activated carbon by chemical activation from biomass using one-step microwave pyrolysis9,17,18,19. So, it is considerably informative and environment-friendly to synthesis biomass-based activated carbon by microwave-assisted H3PO4 activation.
In addition, to improve the adsorption affinities of activated carbon toward specific heavy-metal ions, modification by heteroatom [N, O, sulfur (S), etc.] doping into carbon structures has been proposed, and this has proven to be a desirable method20,21,22,23,24,25,26. Defective sites in or at the edges of a graphite layer can be replaced by heteroatoms to generate functional groups27. Hence, nitrification and reduction modification are used to modify resultant carbon samples to dope N/O functional groups which play a crucial role in efficiently coordinating with heavy metal to form complexing and ion-exchange28.
Based on the findings above, we present a protocol to synthesize N/O dual-doped mesoporous carbon from biomass by chemical activation and two different pyrolysis methods followed up by modification. This protocol also determines which heating method favors the ensuing modification for doping of the N/O functional groups and, thus, enhancing the adsorption performance.

<table border="0" cellpadding="0" cellspacing="0" width="932">
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:269px;">All chemicals and reagents (phosphoric acid, etc.)</td>
			<td style="width:377px;">Nanjing Chemical Reagent Co., Ltd</td>
			<td style="width:119px;"></td>
			<td style="width:167px;">Analytical grade</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Electric furnace</td>
			<td>Luoyang Bolaimaite Experiment Electric Furnace Co., Ltd</td>
			<td></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Microwave oven</td>
			<td>Nanjing Yudian Automation Technology Co., Ltd</td>
			<td></td>
			<td>2.45 GHz frequency</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Surface-area and porosimetry analyzer</td>
			<td>Beijing Gold APP Instrument Co., Ltd</td>
			<td style="width:119px;"></td>
			<td>Vc-Sorb 2800TP</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Fourier transform infrared (FTIR) spectrometer</td>
			<td>Nicolet</td>
			<td style="width:119px;"></td>
			<td>6700</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Flame atomic absorption spectrophotometry</td>
			<td>Beijing Purkinje General Instrument Corporation</td>
			<td style="width:119px;"></td>
			<td>A3</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Element Analyzer</td>
			<td>Germany Heraeus Co.</td>
			<td></td>
			<td>CHN-O-RAPID&#160;</td>
		</tr>
	</tbody>
</table>

preparation of biomass-based mesoporous carbon with higher nitrogen-/oxygen-chelating adsorption for cu(ii) through microwave pre-pyrolysis

An environment-friendly technique for synthesizing biomass-based mesoporous activated carbon with high nitrogen-/oxygen-chelating adsorption for Cu(II) is proposed. Bagasse impregnated with phosphoric acid is utilized as the precursor. To pyrolyze the precursor, two separate heating modes are used: microwave pyrolysis and conventional electric-heating pyrolysis. The resulting bagasse-derived carbon samples are modified with nitrification and reduction modification. Nitrogen (N)/oxygen (O) functional groups are simultaneously introduced to the surface of activated carbon, enhancing its adsorption of Cu(II) by complexing and ion-exchange. Characterization and copper adsorption experiments are performed to investigate the physicochemical properties of four prepared carbon samples and determine which heating method favors the subsequent modification for doping of N/O functional groups. In this technique, based on analyzing data of nitrogen adsorption, Fourier transform infrared spectroscopy, and batch adsorption experiments, it is proven that microwave-pyrolyzed carbon has more defect sites and, therefore, time-saving effective microwave pyrolysis contributes more N/O species to the carbon, although it leads to a lower specific surface area. This technique offers a promising route to synthesis adsorbents with higher nitrogen and oxygen content and a higher adsorption capacity of heavy-metal ions in wastewater remediation applications.

Nitrogen adsorption/desorption isotherms of four samples are presented in Figure 1. All adsorption isotherms show a rapid increase in low P/P0 region and these isotherms belong to type IV (IUPAC classification) demonstrating their pore structure that consists of micropores and dominant mesopores32.
The surface physical parameters for all samples obtained from the n...

Watch this Scientific Journal Video about Preparation of Biomass-based Mesoporous Carbon with Higher Nitrogen-/Oxygen-chelating Adsorption for CuII Through Microwave Pre-Pyrolysis at JoVE.com

Preparation of Biomass-based Mesoporous Carbon with Higher Nitrogen-/Oxygen-chelating Adsorption for CuII Through Microwave Pre-Pyrolysis

Here, we present a protocol to synthesize nitrogen/oxygen dual-doped mesoporous carbon from biomass by chemical activation in different pyrolysis modes followed by modification. We demonstrate that the microwave pyrolysis benefits the subsequent modification process to simultaneously introduce more nitrogen and oxygen functional groups on the carbon.

Preparation of Biomass-based Mesoporous Carbon with Higher Nitrogen-/Oxygen-chelating Adsorption for Cu(II) Through Microwave Pre-Pyrolysis

An environment-friendly technique for synthesizing biomass-based mesoporous activated carbon with high nitrogen-/oxygen-chelating adsorption for Cu(II) is ...

This method can help answer key questions in the utilization of biomass and the wastewater remediation field, such as preparation of modified biomass-based carbon for removal of heavy metals in wastewater. The main advantage of this technique is that the microwave pyrolysis benefits the subsequential modification process to simultaneously introduce more nitrogen and oxygen functional groups of carbon. To begin, rinse the bagasse with deionized water, and put the samples in a drying oven at 100 degrees Celsius for 10 hours.Crush the dried bagasse with a grinder. Then, sieve the powder through a 50-mesh sieve. Now, place 30 grams of fine bagasse powder into a 15-weight-percent phosphoric acid solution in a one-to-one weight ratio for 24 hours.Dry the mixture in an oven at 105 degrees Celsius for six hours. Collect the resulting product as the precursor for bagasse-based activated carbon, or BAC. Now, put 15 grams of the precursor in a microwave oven with a 2.45-gigahertz frequency.Set the power of the microwave oven at 900 watts to pyrolyze the sample for 22 minutes. Ensure a nitrogen flow rate of 20 milliliters per minute with a rotor flow meter. The air inlet of the rotor flow meter is connected to a nitrogen cylinder using a hose, while the outlet is connected to the air inlet of the microwave oven.After allowing the resultant carbon to cool to room temperature in nitrogen, triturate and collect the carbon sample in a beaker. Now, add 300 milliliters of 0.1-molar hydrochloric acid. Stir the mixture using a magnetic stirrer at 200 rpm for more than 12 hours at room temperature.Filter the carbon by filter paper with vacuum filtration. Then, rinse the sample with deionized water until the pH value of the wash water is greater than six. Dry the microwave-pyrolyzed bagasse-based activated carbon, or MBAC, in a vacuum drying oven at 105 degrees Celsius for 24 hours.Mix 50 milliliters of concentrated sulfuric acid and 50 milliliters of concentrated nitric acid in a beaker at zero degrees Celsius. Then, add 10 grams of MBAC to the mixed solution. Use a magnetic stirrer to stir the mixture for 120 minutes at 200 rpm.Filter the nitrified MBAC by filter paper with vacuum filtration. Wash the carbon with deionized water until the wash water reaches pH six. Then, dry the washed carbon in a drying oven at 90 degrees Celsius for 24 hours.In a three-necked flask, add 5.05 grams of the resulting product, 50 milliliters of deionized water, and 20 milliliters of 15-molar ammonium solution. Stir this mixture for 15 minutes with a magnetic stirrer at 200 rpm. Then, add 28 grams of sodium dithionite, and leave the mixture stirring at room temperature for 20 hours.After 20 hours, fit a reflux condenser to the flask, and warm the mixture up to 100 degrees Celsius using an oil bath. Add 120 milliliters of 2.9-molar acetic acid to the flask. Then, allow the mixture to stir for five hours with a magnetic stirrer under reflux.Remove the oil bath to allow the solution to cool down to room temperature. Filter the carbon sample, and wash it with deionized water until the solution pH is greater than six. Dry the modified MBAC at 90 degrees Celsius, and denote it as MBAC-nitrogen.To perform structural characterization through nitrogen adsorption and desorption isotherms, first weigh an empty sample tube. Add approximately 0.15 grams of the carbon sample to the sample tube. Degas the sample at 110 degrees Celsius for five hours in a vacuum.Then, weigh the sample tube containing carbon, and calculate the weight of the carbon sample. Install the sample tube into the test area of the surface area and porosimetry analyzer using liquid nitrogen to measure it at minus 196 degrees Celsius. To perform the chemical characterization using Fourier transform infrared spectroscopy, first check the temperature and hygrometer.The temperature should be 16 to 25 degrees Celsius and the relative humidity 20%to 50%Remove the desiccant and dust cover in the sample storehouse. Dry the carbon sample and potassium bromide at 110 degrees Celsius for four hours to avoid the effect of water on the spectrum. Then, mix the carbon sample with potassium bromide, and use a press mechanism to prepare the test sample.Place the sample in the test area, and set the parameters of the software. Then, save the spectra, and take out the sample before processing the spectra. To perform the copper ion adsorption experiments, first adjust the pH of copper sulfate solutions to pH five using 0.1-molar nitric acid and 0.1-molar sodium hydroxide solutions.Then, place 0.05 grams of adsorbent in each of the conical flasks containing 25 milliliters of the pH-adjusted copper sulfate solutions. Fit lids on the conical flasks, and put them in a thermostatic orbital shaker with a stirring rate of 150 rpm at five degrees Celsius, 25 degrees Celsius, and then 45 degrees Celsius for 240 minutes at each temperature. Use 0.22-micron membrane filters to separate the adsorbents from the solution.Finally, use flame atomic absorption spectrophotometry to determine the copper concentration of the filtrate. Structural characteristics and elemental compositions of all samples are shown here. Microwave pyrolysis and modification contribute to a smaller specific surface area and smaller total pore volume but a greater nitrogen and oxygen content.FTIR spectra show that the modified carbon materials have obtained distinct nitrogen/oxygen functional groups, and the microwave-pyrolyzed carbon gets more. The effect of pH on copper ion adsorption by all samples is shown here. MBAC-nitrogen presents a better copper ion adsorption than EBAC-nitrogen, although MBAC-nitrogen has a lower surface area and pore volume, owing to more abundant nitrogen/oxygen surface groups.In this model, the mechanism for copper ion adsorption by modified carbon is proposed. In this reaction process, the chemical adsorption mainly involves ion exchange and complexing. While attempt to use a Western approach to prepare biomass by based on mesoporous carbon, was better physicochemical properties by microwave pyrolysis.It's important to determine the optimum experimental conditions considering the effect of the impregnation ratio, pyrolysis time, and the microwave oven power. Following this procedure, other modification methods that can effectively introduce more functional groups of the carbon can be performed in order to overcome shortcomings, like the decrease of specific surface area and the total pore volume. After its development, this technique paved the way for researchers in the field of functionalized nanomaterial to explore rapid preparation of high-adsorptive carbon from biomass for wastewater remediation.Don't forget that working with concentrated sulfuric acid and concentrated nitric acid can be extremely hazardous, and precautions such as protective spectacles should always be taken while performing this procedure.

preparation-biomass-based-mesoporous-carbon-with-higher-nitrogen

Research

JoVE Journal

Environment

Measuring Carbon-based Contaminant Mineralization Using Combined CO2 Flux and Radiocarbon Analyses

A method is described which uses the absence of radiocarbon in industrial chemicals and fuels made from petroleum feedstocks which frequently contaminate the environment. This radiocarbon signal &#8212; or rather the absence of signal &#8212; is evenly distributed throughout a contaminant source pool (unlike an added tracer) and is not impacted by biological, chemical or physical processes (e.g., the 14C radioactive decay rate is immutable). If the fossil-derived contaminant is fully degraded to CO2, a harmless end-product, that CO2 will contain no radiocarbon. CO2 derived from natural organic matter (NOM) degradation will reflect the NOM radiocarbon content (usually &#60;30,000 years old). Given a known radiocarbon content for NOM (a site background), a two end-member mixing model can be used to determine the CO2 derived from a fossil source in a given soil gas or groundwater sample. Coupling the percent CO2 derived from the contaminant with the CO2 respiration rate provides an estimate for the total amount of contaminant degraded per unit time. Finally, determining a zone of influence (ZOI) representing the volume from which site CO2 is collected allows determining the contaminant degradation per unit time and volume. Along with estimates for total contaminant mass, this can ultimately be used to calculate time-to-remediate or otherwise used by site managers for decision-making.

Measuring Carbon-based Contaminant Mineralization Using Combined CO2 Flux and Radiocarbon Analyses

A protocol is described wherein CO2 mineralized from organic contaminant (derived from petroleum feedstocks) biodegradation is trapped, quantified, and analyzed for 14C content. A model is developed to determine CO2 capture zone's spatial extent. Spatial and temporal measurements allow integrating contaminant mineralization rates for predicting remediation extent and time.

A method is described which uses the absence of radiocarbon in industrial chemicals and fuels made from petroleum feedstocks which frequently contaminate ...

Preparation and Testing of Impedance-based Fluidic Biochips with RTgill-W1 Cells for Rapid Evaluation of Drinking Water Samples for Toxicity

This manuscript describes how to prepare fluidic biochips with Rainbow trout gill epithelial (RTgill-W1) cells for use in a field portable water toxicity sensor. A monolayer of RTgill-W1 cells forms on the sensing electrodes enclosed within the biochips. The biochips are then used for testing in a field portable electric cell-substrate impedance sensing (ECIS) device designed for rapid toxicity testing of drinking water. The manuscript further describes how to run a toxicity test using the prepared biochips. A control water sample and the test water sample are mixed with pre-measured powdered media and injected into separate channels of the biochip. Impedance readings from the sensing electrodes in each of the biochip channels are measured and compared by an automated statistical software program. The screen on the ECIS instrument will indicate either "Contamination Detected" or "No Contamination Detected" within an hour of sample injection. Advantages are ease of use and rapid response to a broad spectrum of inorganic and organic chemicals at concentrations that are relevant to human health concerns, as well as the long-term stability of stored biochips in a ready state for testing. Limitations are the requirement for cold storage of the biochips and limited sensitivity to cholinesterase-inhibiting pesticides. Applications for this toxicity detector are for rapid field-portable testing of drinking water supplies by Army Preventative Medicine personnel or for use at municipal water treatment facilities.

This manuscript describes how to prepare fluidic biochips with Rainbow trout gill epithelial cells for use in a field portable electric cell-substrate impedance sensor. The protocol for running a rapid drinking water toxicity test with the sensor is also described.

This manuscript describes how to prepare fluidic biochips with Rainbow trout gill epithelial (RTgill-W1) cells for use in a field portable water toxicity ...

Assessment of Labile Organic Carbon in Soil Using Sequential Fumigation Incubation Procedures

Management practices and environmental changes can alter soil nutrient and carbon cycling. Soil labile organic carbon, a readily decomposable C pool, is highly sensitive to disturbance. It is also the primary substrate for soil microorganisms, which is fundamental to nutrient cycling. Due to these attributes, labile organic carbon (LOC) has been identified as an indicator parameter for soil health. Quantifying the turnover rate of LOC also aids in understanding changes in soil nutrient cycling processes. A sequential fumigation incubation method has been developed to estimate soil LOC and potential C turnover rate. The method requires fumigating soil samples and quantifying CO2-C respired during a 10 day incubation period over a series of fumigation-incubation cycles. Labile organic C and potential C turnover rate are then extrapolated from accumulated CO2 with a negative exponential model. Procedures for conducting this method are described.

Labile organic carbon (LOC) and the potential carbon turnover rate are sensitive indicators of changes in soil nutrient cycling processes. Details are provided for a method based on fumigating and incubating soil in a series of cycles and using the CO2 accumulated during the incubation periods to estimate these parameters.

Management practices and environmental changes can alter soil nutrient and carbon cycling. Soil labile organic carbon, a readily decomposable C pool, is ...

Biofilm Removal Using Carbon Dioxide Aerosols without Nitrogen Purge

Biofilms can cause serious concerns in many applications. Not only can they cause economic losses, but they can also present a public health hazard. Therefore, it is highly desirable to remove biofilms from surfaces. Many studies on CO2 aerosol cleaning have employed nitrogen purges to increase biofilm removal efficiency by reducing the moisture condensation generated during the cleaning. However, in this study, periodic jets of CO2 aerosols without nitrogen purges were used to remove Pseudomonas putida biofilms from polished stainless steel surfaces. CO2 aerosols are mixtures of solid and gaseous CO2 and are generated when high-pressure CO2 gas is adiabatically expanded through a nozzle. These high-speed aerosols were applied to a biofilm that had been grown for 24 hr. The removal efficiency ranged from 90.36% to 98.29% and was evaluated by measuring the fluorescence intensity of the biofilm as the treatment time was varied from 16 sec to 88 sec. We also performed experiments to compare the removal efficiencies with and without nitrogen purges; the measured biofilm removal efficiencies were not significantly different from each other (t-test, p &gt; 0.55). Therefore, this technique can be used to clean various bio-contaminated surfaces within one minute.

Biofilms on surfaces can be effectively and rapidly removed by using a periodic jet of carbon dioxide aerosols without a nitrogen purge.

Biofilms can cause serious concerns in many applications. Not only can they cause economic losses, but they can also present a public health hazard. ...

A Flow-through Exposure System for Evaluating Suspended Sediments Effects on Aquatic Life

This paper describes the Fish Larvae and Egg Exposure System (FLEES). The flow-through exposure system is used to investigate the effects of suspended sediment on various aquatic species and life stages in the laboratory by using pumps and automating delivery of sediment and water to simulate suspension of sediment. FLEES data are used to develop exposure-response curves between the effects on aquatic organisms and suspended sediment concentrations at the desired exposure duration. The effects data are used to evaluate management practices used to reduce the interactions between aquatic organisms and anthropogenic causes of suspended sediments. The FLEES is capable of generating total suspended solids (TSS) concentrations as low as 30 to as high as 800 mg/L, making this system an ideal choice for evaluating the effects of TSS resulting from many activities including simulating low ambient levels of TSS to evaluating sources of suspended sediments from dredging operations, vessel traffic, freshets, and storms.

A robust and flexible flow-through exposure system designed to maintain sediment in suspension is presented. The system is used to investigate the effects of suspended sediment on various aquatic species and life stages in the laboratory.

This paper describes the Fish Larvae and Egg Exposure System (FLEES). The flow-through exposure system is used to investigate the effects of suspended ...

Functionalization and Dispersion of Carbon Nanomaterials Using an Environmentally Friendly Ultrasonicated Ozonolysis Process

Functionalization of carbon nanomaterials is often a critical step that facilitates their integration into larger material systems and devices. In the as-received form, carbon nanomaterials, such as carbon nanotubes (CNTs) or graphene nanoplatelets (GNPs), may contain large agglomerates. Both agglomerates and impurities will diminish the benefits of the unique electrical and mechanical properties offered when CNTs or GNPs are incorporated into polymers or composite material systems. Whilst a variety of methods exist to functionalize carbon nanomaterials and to create stable dispersions, many the processes use harsh chemicals, organic solvents, or surfactants, which are environmentally unfriendly and may increase the processing burden when isolating the nanomaterials for subsequent use. The current research details the use of an alternative, environmentally friendly technique for functionalizing CNTs and GNPs. It produces stable, aqueous dispersions free of harmful chemicals. Both CNTs and GNPs can be added to water at concentrations up to 5 g/L and can be recirculated through a high-powered ultrasonic cell. The simultaneous injection of ozone into the cell progressively oxidizes the carbon nanomaterials, and the combined ultrasonication breaks down agglomerates and immediately exposes fresh material for functionalization. The prepared dispersions are ideally suited for the deposition of thin films onto solid substrates using electrophoretic deposition (EPD). CNTs and GNPs from the aqueous dispersions can be readily used to coat carbon- and glass-reinforcing fibers using EPD for the preparation of hierarchical composite materials.

Here, a novel method for the functionalization and stable dispersion of carbon nanomaterials in aqueous environments is described. Ozone is injected directly into an aqueous dispersion of carbon nanomaterial that is continuously recirculated through a high-powered ultrasonic cell.

Functionalization of carbon nanomaterials is often a critical step that facilitates their integration into larger material systems and devices. In the ...

Measurement of the Rheology of Crude Oil in Equilibrium with CO2 at Reservoir Conditions

A rheometer system to measure the rheology of crude oil in equilibrium with carbon dioxide (CO2) at high temperatures and pressures is described. The system comprises a high-pressure rheometer which is connected to a circulation loop. The rheometer has a rotational flow-through measurement cell with two alternative geometries: coaxial cylinder and double gap. The circulation loop contains a mixer, to bring the crude oil sample into equilibrium with CO2, and a gear pump that transports the mixture from the mixer to the rheometer and recycles it back to the mixer. The CO2 and crude oil are brought to equilibrium by stirring and circulation and the rheology of the saturated mixture is measured by the rheometer. The system is used to measure the rheological properties of Zuata crude oil (and its toluene dilution) in equilibrium with CO2 at elevated pressures up to 220 bar and a temperature of 50 &#176;C. The results show that CO2 addition changes the oil rheology significantly, initially reducing the viscosity as the CO2 pressure is increased and then increasing the viscosity above a threshold pressure. The non-Newtonian response of the crude is also seen to change with the addition of CO2.

Measurement of the Rheology of Crude Oil in Equilibrium with CO2 at Reservoir Conditions

A method for measuring the rheology of crude oil in equilibrium with carbon dioxide at reservoir conditions is presented.

A rheometer system to measure the rheology of crude oil in equilibrium with carbon dioxide (CO2) at high temperatures and pressures is described. The ...

Experimental System of Solar Adsorption Refrigeration with Concentrated Collector

To improve the performance of solar adsorption refrigeration, an experimental system with a solar concentration collector was set up and investigated. The main components of the system were the adsorbent bed, the condenser, the evaporator, the cooling sub-system, and the solar collector. In the first step of the experiment, the vapor-saturated bed was heated by the solar radiation under closed conditions, which caused the bed temperature and pressure to increase. When the bed pressure became high enough, the bed was switched to connect to the condenser, thus water vapor flowed continually from the bed to the condenser to be liquefied. Next, the bed needed to cool down after the desorption. In the solar-shielded condition, achieved by aluminum foil, the circulating water loop was opened to the bed. With the water continually circulating in the bed, the stored heat in the bed was took out and the bed pressure decreased accordingly. When the bed pressure dropped below the saturation pressure at the evaporation temperature, the valve to the evaporator was opened. A mass of water vapor rushed into the bed and was adsorbed by the zeolite material. With the massive vaporization of the water in the evaporator, the refrigeration effect was generated finally. The experimental result has revealed that both the COP (coefficient of the performance of the system) and the SCP (specific cooling power of the system) of the SAPO-34 zeolite was greater than that of the ZSM-5 zeolite, no matter whether the adsorption time was longer or shorter. The system of the SAPO-34 zeolite generated a maximum COP of 0.169.

With solar energy as the driving force, a novel adsorption refrigeration system has been developed and experimentally investigated. Water vapor and zeolite formed the working pair of the adsorption system. This manuscript describes the setup of the experimental rig, the operation procedure, and the important results.

To improve the performance of solar adsorption refrigeration, an experimental system with a solar concentration collector was set up and investigated. The ...

Optimized Procedure for Determining the Adsorption of Phosphonates onto Granular Ferric Hydroxide using a Miniaturized Phosphorus Determination Method

This paper introduces a procedure to investigate the adsorption of phosphonates onto iron-containing filter materials, particularly granular ferric hydroxide (GFH), with little effort and high reliability. The phosphonate, e.g., nitrilotrimethylphosphonic acid (NTMP), is brought into contact with the GFH in a rotator in a solution buffered by an organic acid (e.g., acetic acid) or Good buffer (e.g., 2-(N-morpholino)ethanesulfonic acid) [MES] and N-cyclohexyl-2-hydroxyl-3-aminopropanesulfonic acid [CAPSO]) in a concentration of 10 mM for a specific time in 50 mL centrifuge tubes. Subsequently, after membrane filtration (0.45 &#181;m pore size), the total phosphorus (total P) concentration is measured using a specifically developed determination method (ISOmini). This method is a modification and simplification of the ISO 6878 method: a 4 mL sample is mixed with H2SO4 and K2S2O8 in a screw cap vial, heated to 148-150 &#176;C for 1 h and then mixed with NaOH, ascorbic acid and acidified molybdate with antimony(III) (final volume of 10 mL) to produce a blue complex. The color intensity, which is linearly proportional to the phosphorus concentration, is measured spectrophotometrically (880 nm). It is demonstrated that the buffer concentration used has no significant effect on the adsorption of phosphonate between pH 4 and 12. The buffers, therefore, do not compete with the phosphonate for adsorption sites. Furthermore, the relatively high concentration of the buffer requires a higher dosage concentration of oxidizing agent (K2S2O8) for digestion than that specified in ISO 6878, which, together with the NaOH dosage, is matched to each buffer. Despite the simplification, the ISOmini method does not lose any of its accuracy compared to the standardized method.

This paper introduces a procedure to investigate the adsorption of phosphonates onto iron-containing filter materials, particularly granular ferric hydroxide, with little effort and high reliability. In a buffered solution, the phosphonate is brought into contact with the adsorbent using a rotator and then analyzed via a miniaturized phosphorus determination method.

This paper introduces a procedure to investigate the adsorption of phosphonates onto iron-containing filter materials, particularly granular ferric ...

Characterization of Aquatic Biofilms with Flow Cytometry

Biofilms are dynamic consortia of microorganism that play a key role in freshwater ecosystems. By changing their community structure, biofilms respond quickly to environmental changes and can be thus used as indicators of water quality. Currently, biofilm assessment is mostly based on integrative and functional endpoints, such as photosynthetic or respiratory activity, which do not provide information on the biofilm community structure. Flow cytometry and computational visualization offer an alternative, sensitive, and easy-to-use method for assessment of the community composition, particularly of the photoautotrophic part of freshwater biofilms. It requires only basic sample preparation, after which the entire sample is run through the flow cytometer. The single-cell optical and fluorescent information is used for computational visualization and biological interpretation. Its main advantages over other methods are the speed of analysis and the high-information-content nature. Flow cytometry provides information on several cellular and biofilm traits in a single measurement: particle size, density, pigment content, abiotic content in the biofilm, and coarse taxonomic information. However, it does not provide information on biofilm composition on the species level. We see high potential in the use of the method for environmental monitoring of aquatic ecosystems and as an initial biofilm evaluation step that informs downstream detailed investigations by complementary and more detailed methods.

Flow cytometry in combination with visual clustering offers an easy-to-use and fast method for studying aquatic biofilms. It can be used for biofilm characterization, detection of changes in biofilm community structure, and detection of abiotic particles embedded in the biofilm.

Biofilms are dynamic consortia of microorganism that play a key role in freshwater ecosystems. By changing their community structure, biofilms respond ...