Abstract
This work reports the preparation and detailed characterization of stannum indium sulfide (SnIn4S8) semiconductor photocatalyst for degradation of ethiofencarb (toxic insecticide) under visible-light irradiation. The as-prepared SnIn4S8 showed catalytic efficiency of 98% in 24 h under optimal operating conditions (pH = 3, catalyst dosage of 0.5 g L−1). The photodegradation reaction followed pseudo-first-order kinetics. The major intermediates have been identified using gas chromatography/mass spectrometry. •O2− and •OH radicals appeared to be the primary active species in the degradation process as revealed by scavenger and electronic spin resonance studies, while photogenerated holes had a secondary role in this process. A plausible mechanism involving two routes was proposed for ethiofencarb degradation by SnIn4S8 after identifying the major intermediate species: oxidative cleavage of the CH2-S and the amide bonds of the carbamate moiety. Lastly, SnIn4S8 was found to be efficient, stable, and reusable in treating real water samples in three successive photodegradation experiments. This study demonstrates the prospect of SnIn4S8 photocatalysis in treatment of natural and contaminated water from extremely toxic organic carbamates as ethiofencarb.
Highlights
IntroductionCarbamates represent an important class of pesticides with different efficient biological activities that led to its frequent utilization worldwide as insecticides, fungicides, and molluscicides, among other uses [1,2]
The purity of the organic compound was analyzed by high performance liquid chromatography (HPLC)
The main factor in assessment of the photocatalytic activity of a semiconductor is its optical absorption properties, which depend on its band structure [34,35,36]
Summary
Carbamates represent an important class of pesticides with different efficient biological activities that led to its frequent utilization worldwide as insecticides, fungicides, and molluscicides, among other uses [1,2]. Carbamates can pose serious environmental risks and health problems. A recent study, for instance, reported that carbamates were associated to cognitive and neuropsychological impairment, acting as acetylcholinesterase inhibitors [3,4]. Carbamates are found on the list of precedence issued by the United States. Environmental Protection Agency [5]. The major problem with the wide use of carbamates
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
