Adsorption of Pb2+and Cu2+in wastewater by lignosulfonate adsorbent prepared from corn straw

The heavy metal ions contained in industrial wastewater are a great threat to human health. Exploring a adsorbent which have low-cost, green environmental friendly, high adsorption capacity, good recycle is key to solve heavy metal ions pollution. Lignin sulfonate was obtained by treating corn stover, and then modified lignin sulfonate was obtained by hydrothermal method. The porous structure makes heavy metal ions occupy more internal adsorption sites. Modified lignosulfonate adsorbent efficiency removes heavy metals in wastewater especially Cu2+ and Pb2+. The adsorption capacity of Cu2+ on modified lignosulfonate is 450.3 mg g- 1, Pb2+ is 475.4 mg g- 1. In addition, for 40 mg L-1 Cu2+ and Pb2+ using 0.4 g L-1, the adsorption equilibrium is only reached within 60 min. Meanwhile, the removal ratio of Pb is 83 %, Cd is 72 %, Cu is 87 %, Zn is 36 %, Mn is 25 %, Cr is 95 %, and Fe is 99 % in wastewater using 0.4 g L-1 adsorbent in 2 h. This research develops a practical adsorbent to remove heavy metals from actual wastewater.

Automated summary

The heavy metal ions present in industrial wastewater pose a significant threat to human health. To mitigate heavy metal ion pollution, it is crucial to explore an adsorbent that is low-cost, environmentally friendly, exhibits high adsorption capacity, and is easily recyclable. In this study, lignin sulfonate derived from corn stover was modified using a hydrothermal method, resulting in a porous structure that provides more internal adsorption sites for heavy metal ions. The modified lignosulfonate adsorbent efficiently removes heavy metals, particularly Cu2+ and Pb2+, from wastewater, with an adsorption capacity of 450.3 mg/g for Cu2+ and 475.4 mg/g for Pb2+. Additionally, at a concentration of 40 mg/L for Cu2+ and Pb2+, and using a dosage of 0.4 g/L of adsorbent, the adsorption equilibrium is achieved within 60 minutes. Furthermore, the adsorbent achieves removal rates of 83% for Pb, 72% for Cd, 87% for Cu, 36% for Zn, 25% for Mn, 95% for Cr, and 99% for Fe in wastewater within 2 hours. This research demonstrates the development of a practical adsorbent for the removal of heavy metals from real-world wastewater.