Preparation And Adsorption Performance Of Biomass-based Composite Hydrogel

With the development of light chemical industry in China,wastewater pollution caused by heavy metal ions and dyes has become increasingly prominent.Since these pollutants posed potential safety risks to the ecological environment and human health due to its bioaccumulation and non-degradability,therefore,it is urgent to deal with the problem of polluted water.Human beings have researched and developed a series of technologies to reduce water pollution,among which adsorption method was considered to be one of the most convenient and effective methods so far.In this paper,three kinds of multifunctional biomass-based composite adsorbents with low development cost,simple synthesis operation and high wastewater treatment efficiency were prepared and successfully used to remove heavy metal ions and dyes from polluted water,the specific research contents are as follows:（1）GG/SLS adsorbent was prepared by grafting lignosulfonate and guar gum with polyacrylic acid as grafting carrier,the adsorption optimization experiments were carried out with Cu²⁺and Co²⁺as target pollutants.SEM,FTIR,TG,XPS and other characterization methods were used to confirm the successful synthesis of the composite and explored the adsorption mechanism.The adsorption kinetics and isotherms were studied and the maximum monolayer adsorption capacity of Cu²⁺and Co²⁺by GG/SLS was obtained,the competitive adsorption effect of Cu²⁺and Co²⁺in the mixed system was explored.In addition,the regeneration stability experiment showed that the adsorption capacity of GG/SLS for pollutants did not significantly decrease after 5 times of adsorption-desorption.Various results showed that the adsorbent has excellent performance in removing pollutants.（2）For the purpose of studying the removal effect of Cu²⁺and MB,PAA/CMC/AC composite material was successfully prepared by free radical polymerization.Under the action of initiator and crosslinking agent,carboxylic group polymer（polyacrylic acid）was grafted onto carboxymethyl cellulose（CMC）by chain reaction and then physically crosslinking coconut shell activated carbon to form composite hydrogel.The adsorption effect of PAA/CMC/AC on Cu²⁺and MB under different influencing factors was explored,the adsorption capacity of PAA/CMC/AC for Cu²⁺and MB reached 169 mg g^-1and 119.9 mg g^-1,and the adsorption of these two kinds of pollutants by the adsorbent belongs to the chemical adsorption on the multi-molecular layer.At the same time,the presence of MB in the mixed system promoted the adsorption of Cu²⁺.SEM,FTIR,TG,XRD,zeta potential,XPS characterization methods were used to characterize the hydrogel and explain the adsorption mechanism.Finally,the study of recycling experiments confirmed that the PAA/CMC/AC composite material can be reused many times.（3）A composite material（SLS/CMC/BC）were successfully prepared by grafting functionalized waste cotton biochar with lignosulfonate sodium and carboxymethyl cellulose,which was used to remove Pb²⁺and MB in polluted water.The dosage of each synthetic monomer was optimized,and the adsorbent with the best performance was selected for static adsorption experiments under different influencing factors.The results showed that the adsorption capacities of Pb²⁺and MB in single system were 204 mg g^-1and 113 mg g^-1,while the synergistic adsorption in binary system promoted the adsorption of Pb²⁺by SLS/CMC/BC.Adsorption kinetics and isotherm model were established to explain the adsorption mechanism of Pb²⁺and MB by SLS/CMC/BC.Finally,the cyclic adsorption experiment further proved that the adsorbent has good chemical stability and can be used as an adsorbent with broad application prospect.