Treatment of Aquaculture Wastewater through Chitin/ZnO Composite Photocatalyst

Xiajing Lin,Yuanyuan Zhai,Xiujuan Chen,Ed Mcbean,Guohe Huang,Xiong Zhou,Aili Yang

doi:10.3390/w11020310

Abstract

This paper proposed a newly explored composite photocatalyst, Chitin/ZnO, prepared via the sol-gel method for exploring its photocatalytic activity in the simulated aquaculture wastewater under UV irradiation. The study mainly involves the application of Chitin/ZnO from three aspects: the structure, the principle and the degradation efficiency. The effects of purification operation factors including mass ratio rate, dosage, calcination temperature, initial NH4+–N concentration and illumination conditions on the NH4+–N removal effectiveness were investigated. Optimum conditions were explored through orthogonal experiments, which revealed that 88.73% NH4+–N removal from 60 mg/L synthetic wastewater was achieved by direct illumination for 120 min. Additionally, Chitin/ZnO photocatalysts (mass ratio of 2:3) at a calcination temperature of 500 °C were favorable for Chitin loaded over a ZnO lattice. The obtained nanoparticles of Chitin/ZnO were characterized using SEM and X-ray diffraction. The purpose of this paper is to grope for an economical and easy method of Chitin/ZnO powder preparation and to provide a practical approach for future research on the photocatalytic purification of aquaculture wastewater.

Highlights

As the main component of feed raw material, highly concentrated ammonia would seriously interfere with the stability of aquaculture water, leading to adverse effects on wild plants, inhabited animals and human life [1]
The semiconductor photocatalyst doped with non-metallic or metal elements generates a synergistic effect of multiple functions, namely broadening the responsive light zone to improve the utilization of solar light or UV; prohibiting the recombination of light-based electrons and catalyst holes (e− –h+ ), and enhancing the quantitative efficiency of the semiconductor photocatalyst; Water 2019, 11, 310; doi:10.3390/w11020310
The initial concentration of NH –N in the simulated aquaculture wastewater was adjusted by photocatalyst was added, ultraviolet4light would not induce the formation of enough electron–hole the (NH4 )2 SO4 solution to 60 mg/L

Summary

Introduction

As the main component of feed raw material (urea), highly concentrated ammonia would seriously interfere with the stability of aquaculture water, leading to adverse effects on wild plants, inhabited animals and human life [1]. Photocatalytic oxidation is one of the most effective chemical methods. It shows great potential in wastewater purification through inducing the generation of hydroxyl radicals and superoxide anion by irradiating specific semiconductor photocatalysts with band structures such as. The semiconductor photocatalyst doped with non-metallic or metal elements generates a synergistic effect of multiple functions, namely broadening the responsive light zone to improve the utilization of solar light or UV; prohibiting the recombination of light-based electrons and catalyst holes (e− –h+ ), and enhancing the quantitative efficiency of the semiconductor photocatalyst; Water 2019, 11, 310; doi:10.3390/w11020310 www.mdpi.com/journal/water prohibiting the recombination of light-based electrons and catalyst holes (e−–h+), and enhancing the quantitative efficiency of the semiconductor photocatalyst; having an absorption capacity that plays a critical role in physical and chemical reactions.

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Conclusion