Preparation Of Surface Grafting Copolymer On Loess And Its Adsorption Behaviors

Water is an important and essential component of the universe and it plays a vital role in the proper functioning of the earth's ecosystems.With the improvement of industrialization,environmental pollution has become increasingly serious.In spite of the presence of vast water bodies,potable water is not readily available in most parts of the world.This is most dramatic in regions with rapid industrialization and population growth,such as large cities.Over seven hundred organic and inorganic micropollutants in water have been reported.Some of these micropollutants are highly toxic and carcinogenic whilesome have long residence times in the environment and are neither biodegradable nor biotransformable.The loess is a very abundant clay with granule and high hydrophilicity,and was composited with functional polymer of biocompatible monomers.The loess based copolymer used as adsorbents for micropollutant removal from aqueous solution.The content of this thesis includes the following parts:First,this paper introduces the types and applications of polymer modified clays,and summarizes the research progress of the wastewater treatment with modified polymers.Second,the acid activated loess(HLo)as the matrix modified with KH-570 for obtaining C=C.The HLo was modified with biocompatible monomers,sush as N-vinyl-2-pyrrolidone(NVP)and maleic anhydride(MAH),to prepared Lo-PNM.The structure and composition of Lo-PNM were characterized by FT-IR,TG,XRD and SEM.The results showed that NVP,MAH were successfully grafted on the surface of loess.Third,batch experiments were carried out for getting optimum conditions,such as adsorbent dosage of Lo-PNM,contact time,temperature and p H value.The adsorption thermodynamics and kinetics were also investigated.It indicated that Pb(II)removal got to 97.64%,and the decolorization rate of methylene blue(MB)was got to 96.51%.The adsorption of Pb(II)and MB onto Lo-PNM were best fitted with the Langmuir isotherm model and the pseudo-second-order kinetic,respectively.Fourth,using HLo as the matrix modified with KH-570.The HLo was modified with biocompatible monomers,sush as vinyl acetate(VAc),MAH and acrylic acid(AA),to prepared Lo-PVMA.The structure and composition of Lo-PVMA were characterized by FT-IR,TG,XRD and SEM.The results showed that VAc,MAH and AA were successfully grafted on the surface of loess.Fifth,batch experiments were carried out for getting optimum conditions,such as adsorbent dosage of Lo-PVMA,contact time,temperature and p H value.The adsorption thermodynamics and kinetics were also investigated.It indicated that Cu(II)removal got to 97.73%,and the decolorization rate of methylene blue(BF)was got to 98.57%.The adsorption of Cu(II)onto Lo-PVMA was fitted with the Freundlich isotherm model.And adsorption of BF onto Lo-PVMA was best fitted with the Langmuir isotherm model.The kinetics of Cu(II)and BF onto Lo-PVMA were best fitted with pseudo-second-order kinetic,respectively.In a word,loess based polymer adsorbent was prepared by surface grafting copolymerization with a lower proportion of polymer;and the biocompatible adsorbent was prepared by choosing some appropriate copolymer chains.The loess adsorbent has a higher adsorption performance for removing metal ions and decolorating dyes.