Fabrication Of Biomass-based Adsorbents By Grafting Polymerization And Study On Adsorption Properties And Mechanism

Natural biomass materials have the advantages of low cost,good pollution remediation potential,environmental friendliness,easy access and so on.In this study,g-MAA-PS and gAPT-PS were prepared by free radical graft copolymerization with peanut shell and methacrylic acid/（3-acrylamide propyl）trimethyl ammonium chloride as raw materials,and used for the adsorption of positive/anionic dyes and heavy metal pollutants.The adsorption effect and mechanism of the two sorbents were studied as follows:（1）The structure and morphology of g-MAA-PS were characterized and analyzed.The removal of cationic dyes and heavy metal pollutants（methylene blue（MB）,basic red 46（BR）and Cd（II））by g-MAA-PS as adsorbent was investigated.Batch adsorption experiments showed that g-MAA-PS had a faster removal rate of MB,BR and Cd（II）,and reached adsorption equilibrium within 30 min.The adsorption process of the three compounds was more consistent with the description of Langmuir and pseudo-second-order model.At 25℃,the maximum adsorption capacity of MB,BR and Cd（II）is 538.34 mg/g,687.52 mg/g and 62.01mg/g respectively.The co-adsorption experiment of the mixed system shows that g-MAA-PS still has good purification effect on the pollutant solution in the coexistence state of BR and Cd（II）.In addition,g-MAA-PS still showed satisfactory removal performance after 7 repetitions.（2）The morphological characteristics and adsorption effect of g-APT-PS were characterized and evaluated.The removal effect of g-APT-PS as anionic adsorbent on water Congo red and heavy metal chromium was investigated.Under the single pollutant system,g-APT-PS has a good removal effect on Congo red and chromium,reaching adsorption equilibrium at 3 hours and 6 hours,respectively.The adsorption process of the two pollutants accords with the description of Langmuir and pseudo-second-order model.At 45℃,the maximum adsorption capacity of Congo red and chromium is 86.7 mg/g and 9.726 mg/g.After5 cycles of adsorption,g-APT-PS still has good adsorption performance.In conclusion,the two biomass-based adsorbents g-MAA-PS and g-APT-PS prepared by radical graft polymerization in this study have excellent adsorption performance and are efficient and renewable adsorbents,which are expected to have great application potential in the treatment of organic dyes and heavy metal wastewater.