Study On Zero-valent Metal Reduction Of Two Chlorinated Organic Compunds In The Presence Of Tansition Metal Ions

Drugs and personal care products（PPCPs）as a type of emerging water pollutants have attracted widespread attention.Due to human production activities,the composition of the water environment is complex,a variety of pollutants coexist,and compound pollution is formed.In the water environment,there are sometimes phenomena where various heavy metal ions and organic substances coexist,and metal ions have an influence on the reduction characteristics of zero-valent metals,among which the transition metal ions have a certain representativeness.This study examines the zero-valent metal reduction of DCF and TCP in the presence of transition metal ions(Co²⁺,Ni²⁺,Cu²⁺).To investigate the effect of transition metal ion dosage,pH value,dissolved oxygen concentration,and rotation speed on the reaction.After analyzing the morphology and the combination state of the degradation organic products and the sample powders,the reaction mechanism was deduced,thus providing data support for practical application.Test results show that transition metal ions can effectively accelerate zero-valent metal reduction of DCF and TCP.The zero-valent zinc dosage was 10 g·L^-1,and the transition metal ion dosage was 1 mmol·L^-1.After 72hours of reaction,the DCF removal rate reached more than 67.8%.Among of them,zero-valent zinc has the best effect of reducing DCF in the presence of nickel ions,and DCF removal rate is over 99%;The zero-valent iron dosage is 10 g·L^-1,and the transition metal ion dosage is 2mmol·L^-1.After 24 hours of reaction,the removal rate of TCP is up to 30%.Among of them,Cu²⁺has the best effect of removing TCP with zero price iron,and the removal rate can reach 80%.The above transition metal ion dosage has a positive correlation with the removal rate of DCF and TCP;Excessive rotational speed and alkaline conditions inhibit the reaction;Dissolved Oxygen Inhibition Occurs at Dissolved Oxygen Concentration0⁸ mg·L^-1,When the concentration of dissolved oxygen reached 20mg·L^-1,the reaction of dissolved oxygen was accelerated;In the transition metal ion system,the lower the pH,the higher the removal rate of DCF and TCP and the faster the reaction rate.The product analysis shows that DCF has different products under different reaction conditions.In the presence of Co²⁺and Ni²⁺,two products were formed.In the presence of Cu²⁺,only one product was formed;The SEM analysis of the zinc powder after the reaction found that the presence of different transition metal ions will generate different lines on the surface of the zero-valent zinc,and that the zero-valent zinc surface covers more particles may passivate the surface of the zero-valent zinc.XRD analysis results show that in the presence of transition metal ions,it may accelerate the corrosion of zero-valent zinc and generate more active hydrogen;The results of XPS analysis shows that in the presence of transition metal ions,the transition metal ion morphology will change,and they will generate Co₃O₄,Ni（OH）₂ and Cu₂O.Among them,Co₃O₄ and Ni（OH）₂ will promote water dissociation.Generate more reduced hydrogen,the new ecological Cu₂O can improve the ability of zero-valent zinc reduction and generate more active hydrogen;TCP has not been detected under different conditions,and the surface morphology of zero valent iron is different in the presence of different transition metal ions,which may affect the removal of TCP by zero valent iron.The reaction mechanism for removing DCF is presumed to be catalytic hydrogenation,and the reaction mechanism for removing TCP may be physical adsorption.