Research On The Preparation Of Modified Phosphorous Slag And Its Adsorption Performance Of As(Ⅲ) From Wastewater

Arsenic and arsenic compounds have great toxic to human health,arsenic pollution has become more and more concerned,especially the increasingly serious arsenic pollution in water,With the rapid development of phosphorus chemical industry,a large number of phosphorus slag cannot be fully utilized,and cause harm to the environment.This study adopts the phosphorus slag as adsorption material of arsenic,and will be modified to improve the adsorption of arsenic,not only prepared a kind of environmental material of removing arsenic in the wastewater,but also provides a new way for the comprehensive utilization of phosphorus slag,and solved two environmental problems,achieved the effect of using waste treat waste.Be screened out of ferric salt constant infiltration and ferric salt ultrasonic assisted from a variety of methods to modification of phosphorous slag,and the experimental condition of modification is optimized.The results showed that the optimal preparation conditions of ferric salt constant infiltration are as follows:0.8mol·L-1 of FeC13 dipping,curing temperature 80℃ and curing time 6h,and the removal rate of As(Ⅲ)in wastewater was improved to 99.1%;the optimal preparation conditions of ferric salt ultrasonic assisted are as follows:0.8mol L-1 of FeC13,and ultrasonic time of 15 min,and the removal rate of As(III)in wastewater was improved to 98.9%.Compared with the unmodified,two kinds of modified phosphorus slag increased respectively by 38.2%and 38%of the As(Ⅲ)removal rate in wastewater.Coexisting ions have a certain influence on the two kinds of modified phosphorus slag adsorption of As(Ⅲ),when the concentration of the As(Ⅲ)is fixed,the influence of the order:SiO32-.PO43->SO42->CO32-.Cl-;contrary,the influence of the order:SiO32-、PO43->SO42-、CO32-、Cl-,The influence of SiO32-and PO43-is bigger.Desorption of two kinds of modified phosphorus slag after absorption with NaOH solution,after three times desorption,the As(Ⅲ)removal rate remained stable,shows that two modified phosphorus slag had good regeneration performance.The methods BET,FT-IR,SEM/EDS and XPS were used to analyze the difference of the phosphorous slag before and after modification and after absorption.After modification,the BET and pore volumes of phosphorous slag increased,and average pore diameters decrease,the content of Fe3+ and-OH rised,there is As(Ⅲ)and As(Ⅴ)in the phosphorus slag of after the adsorption,shows that two modified methods can make the ferric good load on the phosphorus slag,increase its ability of removing As(Ⅲ).The adsorption isotherm and kinetic equation of adsorption As(Ⅲ)by the two kind of modified phosphorus slag were simulation.The adsorption isotherm could satisfy both isotherm model of Langmuir and Freundlich simultaneously,but the Langmuir isotherm model has a better description of the adsorption process,thefitting correlation coefficient R2 is 0.99 and 0.98 respectively,the adsorption methods were mainly based on monolayer adsorption.The adsorption process of the two kind of modified phosphorus slag is well described by Lagergren pseudo second-order kinetics equation,the equilibrium adsorption capacity theoretical values of fitting and experimental values are close,and the fitting correlation coefficient R2 is 0.97 and 0.96 respectively,the adsorption rate is controlled by chemical adsorption.