Adsorption And Photocatalytic Degradation Of Low Concentration Ammonia Nitrogen From Aqueous Solution Under BiOI/BiOBr/MoS₂ Composite Treatment

With the increasing discharge standard of ammonia nitrogen in wastewater,the excessive ammonia concentration in the effluent of many enterprises has become an urgent problem to be solved.Besides,low concentration ammonia wastewater exists in some micro-polluted source water and aquaculture wastewater,which is a research and development object in water treatment field.Therefore,a simple process with high degradation efficiency of low concentration ammonia wastewater has been developed in this paper,with this process,the concentration of ammonia nitrogen in wastewater can reach a discharge standard and can be recycled.A novel photocatalyst powder,Bi OI/Bi OBr/Mo S_2,was synthesized by a simple solvothermal method.X-ray diffraction?XRD?,specific surface area and pore size analyses,scanning electron microscopy?SEM?,transmission electron microscopy?TEM?,and X-ray energy spectrometry?EDS?were utilized to characterize the prepared samples.Composite material powder is stacked in sheet shape with 13.46 m²/g specific surface and 16.16 nm pore diameter.NH₄Cl was used to simulate ammonia wastewater to evaluate the photocatalytic performance of the catalyst.Evaluating the effect of different p H,reaction time and initial concentration of the solution to the photocatalytic efficiency.At the condition of p H=10,50 mg/L initial concentration,after 120 min UV light irradiation,the degradation of ammonia wastewater by 1 wt%Mo S₂composite is 82.98%.Compared to Bi OBr material,composites have better adsorption-photocatalytic efficiency under Xe light.The result of simulated ammonia wastewater removal efficiency by composite with different loading ratios show that 1 wt%Mo S₂ is the optimal loading ratio of composite.In order to solve the problem of losing powder and secondary pollution in treating ammonia wastewater by composite material,Bi OI/Bi OBr/1 wt%Mo S₂ was loaded on the glass fiber and carbon fiber by polyvinylidene fluoride?PVDF?and N-methylpyrrolidone,respectively.At the condition of p H=10,50 mg/L initial concentration,after 90 min Xe light irradiation,the degradation of ammonia simulate wastewater by loaded glass fiber and loaded carbon fiber are 88.20%and 78.30%,after 4 times reuse,the degradation is 74.10%and 60.58%,respectively.At the end of this paper,Infrared spectroscopy?FTIR?was utilized the adsorption capacity of the composite material.The higher the adsorption rate,the higher the photocatalytic activity.The degradation mechanism of ammonia nitrogen was synthesized by measuring the content of nitrate nitrogen and total nitrogen after the photocatalytic reaction.According to the low concentration of nitrate nitrogen and the concentration of total nitrogen which close to the concentration of ammonia nitrogen,it is speculated that the degraded ammonia nitrogen is converted into gaseous nitrogen compounds through photocatalytic reaction.