Preparation of Sodium Lignosulfonate/Chitosan Adsorbent and Application of Pb2+ Treatment in Water

Industrial wastewater has brought huge disasters to water resources and soil and has seriously affected the growth of animals and plants. There is an urgent need for a green and efficient adsorbent to solve the problem of water pollution. Sodium lignosulfonate and chitosan undergo free radical polymerization to form a lignin/chitosan adsorbent, which is used to treat Pb2+ in water pollution. An orthogonal experiment was used to optimize the content of sodium lignosulfonate, chitosan, cross-linking agent and initiator to obtain the adsorbent with the best adsorption performance. The adsorbents were characterized by Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), thermal analysis and zeta potentiometry. The influence of different conditions on the adsorption of heavy metal ions by lignosulfonate/chitosan adsorbent was explored, and a kinetic and isotherm model was established. The results showed that the adsorption capacity of Pb2+ was 345 mg g−1 when the adsorbent was 0.01 g, the concentration of heavy metal ions was 100 mg L−1 and pH was 7. The adsorption process of lignosulfonate/chitosan is a kind of spontaneous adsorption mode, which is mainly composed of electrostatic adsorption and chemical adsorption.