A removal of emerging contaminant antimony from surface waters is highly demanded. The most abundant antimony species are antimony three and antimony five, and antimony three is 10 times more toxic than antimony five. A two-step oxidation precipitation strategy is commonly adopted for antimony three removal, that is to oxidize antimony three to antimony five firstly, followed by chemical precipitation.
But we could achieve this within a single unit. Since antimony shares similar physical chemical properties with other elements from the same nitrogen group, like arsenic or phosphorus, I believe this method could also be extended to these compounds. Be sure to read the SDS of all of the chemicals carefully.
Follow the protocol and the incumbent instructions closely, and learn how to differentiate between antimony three and five. Minor changes in the protocol may cause significant changes in the system performance. For example, too much titanate may deter your rate of conductivity and antimony three removal kinetics of the filter.
To prepare the titanate nano wires, first dissolve 56 grams of potassium hydroxide in 100 milliliters of de-ionized water under vigorous stirring. Next add 3 grams of titanium dioxide powder to the solution. Entrance for the solution into a Teflon lined reactor.
Hold the solution at 200 degrees Celsius for 24 hours. Before washing the resulting white precipitate with 0.1 mols per liter of hydraulic acid and de-ionized water, until a neutral affluent pH is obtained. Dry the product under vacuum at 60 degrees Celsius overnight.
Then transfer the product to a tube furnace and heat the material to 600 degrees Celsius for 2 hours with a ramp rate of 1 degree Celsius per minute. For titanate CNT filter preparation, add 20 milligrams of CNT's into 40 milliliters of N-Methyl pyrrolidone and probe sonicate the mixture for 40 minutes to obtain a homogenous solution. Next add 200 milligrams of the titanate nano wires to 20 milliliters of methyl pyrrolidone and probe sonicate the mixture for 20 minutes.
At the end of the sonication, mix the titanate dispersion solution with the CNT dispersion solution and filter the resulting mixture onto a PTFE membrane. Then rinse the filter one time with 100 milliliters of ethanol, and one time with 200 milliliters of de-ionized water. For electrochemical antimony filtration, first add 2.2 milligrams of potassium antimonyl tartrate trihydrate to 1, 000 milliliters of de-ionized water before adding 100 milliliters of the resulting 800 micrograms per liter antimony solution to a 150 milliliter beaker.
Adjust the solution to a pH of 7, and place the prepared titanate CNT filter anode into an electrochemistry modified polycarbonate filtration casing. Place a CNT-alone filter into the casing as the cathode, and connect the anode and cathode with a perforated titanium ring. Use insulating silicone rubber to separate and seal the casing, and pass the antimony solution through the filtration system at an appropriate flow rate, using a DC power supply to apply the correct voltage during the filtration.
At the end of the filtration, use an atomic fluorescent spectrometer to determine the total antimony and antimony three concentrations according to standard protocols. The electro active filtration apparatus is an electrochemically modified polycarbonate filtration casing. Field emission scanning electron microscope images of the titanate CNT filter suggest a roughened surface.
Transmission electron microscopy characterization suggests that the CNT's are entangled with the titanate nano wires after processing, indicating a successful synthesis of the titanate-CNT hybrid material. To demonstrate the efficacy of the electrochemical filtration system, the change of the antimony total and the antimony valence state as a function of time can be determined. For example, in this representative analysis, the antimony five concentration rose sharply within the initial 30 minutes.
While a complete antimony three conversion was observed over 1 hour of continuous filtration in the recirculation mode, indicating the antimony three oxidation was the main reaction process in the initial stage, allowing the antimony five to be absorbed effectively by the loaded titanate nano wires. Furthermore, both the antimony sorption kinetics and capacity increased with the applied voltage due to the enhanced electrostatic interactions and near the surface transport by electro migration. This protocol is dedicated to provide a promising strategy by integrating complicated tasks, membrane science, and electro-chemistry for the decontamination of antimony three and other similar components in water.
Using the fabricated filter as a cathode filtration system at the function or reduction and absorption may be demonstrated. Allowing the decontamination of other heavy metal ions like chromium six. In the next step we plan to investigate the impact of natural organic materials on the antimony three removal performance as well as dedicated to develop lab features to achieve improved kinetics.
Some of the chemicals are toxic, corrosive, or irritants. Be sure to always wear the appropriate personal protection equipment during their use.
