Study on Modified Loaded Chitosan Adsorbent Based on Mercapto-alkenyl Click Reaction and Adsorption of Pb(II)

Industrialization has caused serious heavy metal pollution in water resources, which is harmful to human health. It is of great significance to use heavy metal removal technology to ensure water safety. In this study, a new kaolin/chitosan composite (TGL-CS) was prepared for the adsorption of lead-containing wastewater based on the mercapto-alkenyl base reaction strategy. The effects of pH, adsorbent dosage and ionic strength on the adsorption performance of TGL-CS were investigated. The adsorption process of Pb(II) on TGL-CS is consistent with the Langmuir isotherm and pseudo-second-order kinetic model. The maximum adsorption capacity of TGL-CS for Pb(II) was 87.72 mg/g. The adsorption mechanism of TGL-CS is mainly the coordination between Pb(II) and hydroxyl, amino and sulfur-containing groups. In particular, the click chemical reaction does not consume the amino group in chitosan but also introduces the sulfur-containing group to improve the adsorption capacity of heavy metals. In addition, the ionic strength in the environment system has little effect on the adsorption of Pb(II) by TGL-CS, and the reusability of TGL-CS is high. In summary, TGL-CS has the advantages of low cost, simple preparation, and broad application prospects in the treatment of heavy metal-polluted water bodies.