Adsorption Properties Of Acrylic Composite Natural Organic Molecular Hydrogel

The unrestrained demand and improper use of nature by human lead to the lack of natural resources and serious environmental pollution.The bad water environment pollution poses a great threat to the survival safety of human beings,animals and plants,so it is urgent to deal with the pollution.In this paper,three kinds of heavy metal ion adsorbents based on polyacrylic acid were synthesized by radical polymerization:polysaccharide adsorbent?GL/CS?complexed with chitosan and dextran,sodium lignin sulfonate and lysine forming adsorbent?CSL-Lys?,and sodium lignin sulfonate and citric acid forming adsorbent?CCLS?.The adsorption performance of the adsorbents was optimized and the adsorption effect of the adsorbent on heavy metal ions was studied.The details are as follows:?1?Based on acrylic acid,chitosan and dextran were compounded by an initiator and a cross-linking agent under the assistance of ultrasound to form a GL/CS adsorbent.Scanning electron microscopy,Fourier infrared spectroscopy,Thermal analysis and other characterization methods were used to characterize the GL/CS adsorbent.The adsorption performance of the GL/CS adsorbent was evaluated by different pH,amount of adsorbent,adsorption time,and concentration of heavy metal ions,and the two kinetic models and four isotherm models were used to study the adsorption principle.It was found that at pH=7,the amount of adsorbent was 0.01 g,and the concentration of metal ions was 100 mg g^-1,the adsorption capacity of GL/CS adsorbent for Cu²⁺,Co²⁺,Ni²⁺,Pb²⁺,and Cd²⁺was 342 mg g^-1,232 mg g^-1,184 mg g^-1,395 mg g^-1,269 mg g^-1.The studies have shown that the adsorption process of heavy metal ions by GL/CS is a single molecule chemical adsorption process.?2?Based on polyacrylic acid resin,sodium lignin sulfonate and lysine are combined under the action of initiator and cross-linking agent to form CLS-Lys adsorbent.In the synthesis experiment,response surface method was used to optimize the content of sodium lignosulfonate,lysine,initiator and crosslinking.The CLS-Lys adsorbent is characterized by Fourier transform infrared spectroscopy,scanning electron microscopy,thermal analyzer and zeta potential analyzer.The performance of CLS-Lys adsorbent under different influencing factors is studied.The kinetic and isothermal models of CLS-Lys adsorbent are established.The results show that the main adsorption model of CLS-Lys adsorbent is chemical adsorption,accompanied by electrostatic adsorption.These two ions have a competitive adsorption relationship,and when the two ions are present at the same time,they inhibit each other.In addition,CLS-Lys adsorbent has good adsorption and regeneration performance.It is an economic and effective adsorbent,and has a broad application prospect.?3?Sodium ligninsulfonate/citric acid?CCLS?adsorbent was obtained by free-radical polymerization using acrylic acid with sodium lignosulfonate and citric acid.FTIR,SEM,TGA and XPS characterization methods were used to prove the structure and properties of CCLS adsorbents.CCLS adsorbent has good adsorption performance.The adsorption content for Cu ions is 276 mg g^-1,and the adsorption capacity for Pb ions is 323 mg g^-1.The kinetic,isotherm,and XPS characterizations demonstrated that CCLS adsorbents adsorb Cu and Pb ions in the way of coordination and electrostatic attraction.At the same time,after five regeneration experiments,the adsorption efficiency of CCLS adsorbent for Cu ion and Pb ion is 82%and 85%,respectively.On the basis of cheap polyacrylic acid resin,a green lignin-based adsorbent with strong environmental protection and regeneration ability was developed.