Industrial lignins: the potential for efficient removal of Cr(VI) from wastewater

Cr(VI), a serious threat to human health, widely exists in the effluents of various industrial processes.. In this paper, the potential of industrial lignin for efficient removal of Cr(VI) from wastewater were systematacially investigated, including pulping black liquor lignin (BLN), enzymolysis lignin (ELN), and SPORL pretreatment spent liquor (FS). The structure characterizations of three lignins were investigated by TG, FTIR, BET, SEM, and XPS. Among these three lignins, BLN showed the highest adsorption amount of Cr(VI) and best selectivity in wastewater simulation. According to the Langmuir model, the calculated maximum adsorption amount of Cr(VI) on ELN, BLN, and FS was 765.60, 880.57, and 721.58 mg g − 1 , respectively. The adsorption of Cr(VI) by industrial lignins was a chemisorption process, during which Cr(VI) was reduced to low toxic Cr(III). This paper provided a promising application for the effective utilization of industrial lignins.