Layered double hydroxides loaded sludge biochar composite for adsorptive removal of benzotriazole and Pb(II) from aqueous solution

In this work, a novel sludge biochar/Zn-Al layered double hydroxide composite (SL) was synthesized in a facile co-precipitation method, and it was used to simultaneously remove benzotriazole (BTA) and lead ion (Pb(II)). Batch adsorption experiments demonstrated that composites with sludge content of 1.0 g (SL-1.0) had a great adsorption performance for BTA and Pb(II). The maximum adsorption capacities of SL-1.0 for BTA and Pb(II) were 239.6 and 226.1 mg g-1, respectively. There was preferential adsorption of BTA in BTA and Pb(II) binary system. The adsorption mechanism analysis indicated that the BTA and Pb(II) adsorption involved electrostatic attraction and chemical bonding with surface functional groups on SL-1.0. Specifically, hydrogen bonding and 7C-7C interaction were mainly ascribed to BTA adsorption, while complexation with surface function groups dominated Pb(II) adsorption. With the advantages of facile synthesis and excellent adsorption capacity, SL-1.0 possesses great potential for simultaneously removing of BTA and Pb(II) from wastewaters.

Automated summary

A novel composite material SL-1.0 was synthesized in this study, which demonstrated great potential for simultaneous removal of benzotriazole and lead ion from wastewaters due to its facile synthesis and excellent adsorption capacity. The adsorption mechanism involved electrostatic attraction and chemical bonding with surface functional groups, with hydrogen bonding and 7C-7C interaction mainly contributing to benzotriazole adsorption and complexation with surface function groups dominating lead ion adsorption.