Preparation Of The Functionalized Nano-Silica And Cobalt Oxide(?,?)for The Adsorption And Removal Of Arsenic

Arsenic pollution is a serious social problem that seriously jeopardizes people's health.In particular,the pollution of water has caused widespread concern worldwide,and it is extremely urgent to carry out the treatment of arsenic pollution.With its environmental friendliness,high efficiency,economy and easy operation,adsorption method has become the main method for arsenic removal.However,most adsorbents can only effectively remove As?V?,and the effect on As?III?is not ideal.Therefore,the development of?the?new adsorbents with a wide range of applications and strong adsorption capacity is a goal which researchers have been pursuing.It is also an effective way to remove As?III?and As?V?at the same time.In this dissertation,two nanomaterials were prepared as novel arsenic removal sorbents for simultaneous removal of arsenate?As?V??and arsenite?As?III??from water.The main contents are summarized as follows:1?The introduction mainly summarizes the physicochemical properties of arsenic and its effects on human health,and various methods of arsenic removal are introduced.The advantages of adsorption method of removing arsenic are emphasized.Then the application and significance of mesoporous silica and metal oxide in adsorption are introduced.At the end,the main research work and practical significance of this paper are briefly introduced.2?In this chapter,mesoporous silica?SBA-15?,with large specific surface area and high stability,was used as a matrix to graft thiol and amino by the ring-opening click reaction for the first time.The synthesized novel adsorbent?bi-SBA-15?contains abundant active sites which can adsorption As?III?and As?V?by chelation and electrostatic interaction,respectively,so that two forms of arsenic in water can be simultaneously removed.Within 5 min,the removal efficiency of bi-SBA-15 on As?III?and As?V?were 83.55%and 85.92%,respectively.The thiol and amino in bi-SBA-15 had a synergistic effect in the process of removing arsenic,which greatly improves the adsorption capacity of bi-SBA-15 for arsenic.The adsorption isotherms showed that the maximum adsorption capacities of bi-SBA-15 for As?III?and As?V?were 33.70 mg/g and 42.66 mg/g,respectively.In this paper,a new and simple method for modifying mesoporous silica was proposed,which exhibited excellent performance in arsenic removal and had good practical application potential.3?In this chapter,cobalt monoxide?Co₃O₄?)nanomaterials were prepared by simple hydrothermal method.For the first time,they were used as arsenic adsorbents to simultaneously remove As?III?and As?V?from water,and the removal mechanism was studied and discussed.Co₃O₄ can effectively adsorb As?III?and As?V?under complexation and electrostatic interaction,and can oxidize As?III?to less toxic As?V?,which reduces secondary pollution to the environment.In addition,the effects of initial arsenic concentration,adsorption time,pH and coexisting anions on the adsorption properties of Co₃O₄ were investigated.The adsorption of Co₃O₄ in As?III?and As?V?mixed solution was investigated.The results showed that Co₃O₄ could efficiently adsorb arsenic in a complex environment.Kinetic model was used to analyze the adsorption process,and it was found that the adsorption of arsenic by Co₃O₄ was a chemical process.In addition,Co₃O₄ has a good recycling capacity and is an efficient adsorbent for arsenic removal.