A Complete Method for Evaluating the Performance of Photocatalysts for the Degradation of Antibiotics in Environmental Remediation

Summary

Presented here is a protocol to explore a universal set of experimental procedures for comprehensive laboratory evaluation of photocatalysts in the field of environmental purification, using the example of photocatalytic removal of antibiotic organic pollutant molecules from water by phthalocyanine sensitized silver phosphate composites.

Abstract

Various antibiotics such as tetracycline, aureomycin, amoxicillin, and levofloxacin are found in large quantities in groundwater and soil systems, potentially leading to the development of resistant and multi-drug resistant bacteria, posing a threat to humans, animals, and environmental systems. Photocatalytic technology has attracted keen interest due to its rapid and stable treatment and direct use of solar energy. However, most studies evaluating the performance of semiconductor catalysts for the photocatalytic degradation of organic pollutants in water are currently incomplete. In this paper, a complete experimental protocol is designed to comprehensively evaluate the photocatalytic performance of semiconductor catalysts. Herein, rhombic dodecahedral silver phosphate was prepared by a simple solvent phase synthesis method at room temperature and atmospheric pressure. BrSubphthalocyanine/Ag₃PO₄ heterojunction materials were prepared by the solvothermal method. The catalytic performance of as-prepared materials for the degradation of tetracycline was evaluated by studying different influencing factors such as catalyst dosage, temperature, pH, and anions at atmospheric pressure using a 300 W xenon lamp as a simulated solar light source and a light intensity of 350 mW/cm². Compared with the first cycle, the constructed BrSubphthalocyanine/Ag₃PO₄ maintained 82.0% of the original photocatalytic activity after five photocatalytic cycles, while the pristine Ag₃PO₄ maintained only 28.6%. The stability of silver phosphate samples was further tested by a five-cycle experiment. This paper provides a complete process for evaluating the catalytic performance of semiconductor catalysts in the laboratory for the development of semiconductor catalysts with potential for practical applications.

Introduction

Tetracyclines (TCs) are common antibiotics that provide effective protection against bacterial infections and are widely used in animal husbandry, aquaculture, and disease prevention^1,2. They are widely distributed in water due to their overuse and improper application in the past decades, as well as the discharge of industrial wastewater³. This has caused severe environmental pollution and serious risks to human health; for example, the excessive presence of TCs in the aqueous environment can negatively affect microbial community distribution and bacterial resistance, leading to ecolog....

Protocol

1. Preparation of the BrSubPc

NOTE: The BrSubPc sample was prepared according to a previously published work³⁶. The reaction is carried out in a double-row tube vacuum line system, and the reaction process is strictly controlled under water-free and oxygen-free conditions.

1. Pre-treatment of raw materials
   1. Weigh 2 g of o-dicyanobenzene, dry it in a vacuum oven for 24 h, take it out and then grind it carefully in an agate mortar.

Discussion

In this paper, we present a complete methodology for evaluating the catalytic performance of photocatalytic materials, including the preparation of catalysts, the investigation of factors affecting photocatalysis, and the performance of catalyst recycling. This evaluation method is universal and applicable to all photocatalytic material performance evaluations.

In terms of material preparation methods, many schemes have been reported for the preparation of rhombic dodecahedral Ag₃PO.......

Materials

Name	Company	Catalog Number	Comments
300 W xenon lamp	CeauLight	CEL-HXF300
AgNO3	Aladdin Reagent (Shanghai) Co., Ltd.	7783-99-5
Air Pump	Samson Group Co.	ACO-001
BBr3	Bailingwei Technology Co., Ltd.	10294-33-4
Constant temperature circulating water bath	Beijing Changliu Scientific Instruments Co.	HX-105
Dichloromethane	Tianjin Kemiou Chemical Reagent Co., Ltd.	75-09-2
Ethanol	Tianjin Fuyu Fine Chemical Co., Ltd.	64-17-5
Fourier-transform infrared	Bruker	Vector002
Hexane	Tianjin Kemiou Chemical Reagent Co., Ltd.	110-54-3
HNO3	Aladdin Reagent (Shanghai) Co., Ltd.	7697-37-2
ICP-OES	Aglient	5110
K2HPO4	Aladdin Reagent (Shanghai) Co., Ltd.	16788-57-1
Magnesium Sulfate	Tianjin Kemiou Chemical Reagent Co., Ltd.	10034-99-8
Methanol	Tianjin Kemiou Chemical Reagent Co., Ltd.	67-56-1
NaOH	Aladdin Reagent (Shanghai) Co., Ltd.	1310-73-2
NH4NO3	Sinopharm Group Chemical Reagent Co., Ltd.	6484-52-2
o-dichlorobenzene	Tianjin Fuyu Fine Chemical Co., Ltd.	95-50-1
o-dicyanobenzene	Sinopharm Group Chemical Reagent Co., Ltd.	91-15-6
Scanning electron microscopy	JEOL	JSM-6390
Trichloromethane	Tianjin Kemiou Chemical Reagent Co., Ltd.	67-66-3
Ultraviolet-visible Spectrophotometer	Shimadzu	UV-3600
X-ray diffractometer	Rigaku	D/max-IIIA