Study On Preparation Of Amino-modified Cellulose And Application In Cu²⁺ Adsorption

Heavy metal pollution is a serious threat to the balance of the ecological system of nature and people’s health. Copper has been known as one of the most common toxic metals; Copper is necessary for life processes in trace quantity. Nevertheless, continued intake of copper by human beings leads to necrotic changes in the liver and kidneys, gastrointestinal irritation, widespread capillary damage, and lung cancer. Thus, removal of copper metal ions from wastewater resources has become a primary technique in obtaining clean water for drinking purposes. Due to attractive characteristics as being environmentally friendly, highly efficient with little secondary pollution, cellulose has become focus of research on separation and recovery of heavy metal ions.Adopting click chemistry and grafting polymerization, the modified cellulose adsorbent Cell-g-PGMA-click-PPA and polyamino-functionalized cellulose adsorbent Cell-g-PAN-TEPA were prepared with microcrystalline cellulose as raw materials in this paper. The modified cellulose adsorbents were characterized by FT-IR, elemental analysis and DTG/TGA.The effects of pH, contact time, initial adsorption concentration and on adsorption of Cu2+as well as regeneration performance of adsorbents were investigated.Static adsorption research results showed that the optimal pH for the removal of Cu2+ for Cell-g-PGMA-click-PPA and Cell-g-PAN-TEPA was 5.2 and 5.0, respectively. The data agreed well with pseudo-second-order model based on the assumption that the rate-limiting step may be chemisorption involving valency through sharing electrons between adsorbent and heavy metallic cation. Meanwhile, within 240-350 min, the adsorption equilibrium between Cu2+ and both of the two adsorbents could be established. The adsorption isotherms of Cu2+ can be interpreted by the Langmuir model.The corresponding dynamic adsorption capacity obtained from the column tests was 79.4 mg g-1 for Cell-g-PGMA-click-PPA and 161.3 mg g-1 for Cell-g-PAN-TEPA. The adsorption capacity for Cu2+ remained above 80% of the maximum adsorption capacity after the fifth regeneration cycle, indicating that adsorption and desorption efficiency of Cell-g-PGMA-click-PPA and Cell-g-PAN-TEPA for Cu2+ was fairly satisfactory.