Preparation of modified sodium alginate aerogel and its application in removing lead and cadmium ions in wastewater.

A low-cost, environment-friendly sodium alginate-meso-2,3-dimercaptosuccinic acid hybrid aerogel (SA-DMSA) was synthesized by simple chemical grafting and vacuum freeze-drying method and used to remove heavy metal ions in wastewater. The as-prepared SA-DMSA showed high affinity for heavy metal ions, such as Pb2+, Cd2+, Cu2+, Cr3+, and Co2+, and can remove >90% of the metal ions from the corresponding solution. SA-DMSA also exhibited high selectivity to Pb2+ and Cd2+, and the maximum adsorption capacities for Pb2+ and Cd2+ reached 116.4 and 91.2 mg/g, respectively. The SA-DMSA adsorbent can be regenerated by a simple one-step acid washing, and the adsorption performance remained stable after repeated use. Given its low-cost and easy-to-obtain raw materials, simple preparation process, and simple regeneration process of the adsorbent, SA-DMSA has broad application prospects in the treatment of low-concentration heavy metal ions, especially for wastewater containing Pb2+ and Cd2+.