Innovative recovery of winemaking waste for effective lead removal from wastewater

Abstract

Every year, important quantities of winemaking waste create problems for wine producers. These problems arise from the difficulty of disposing of grape marc, which can pollute the environment and affect nearby agricultural crops. The present research proposes a new direction for the valorization of this agri-food waste in residual water depollution. Four biomaterials obtained from winemaking waste were tested for Pb removal: Raw Merlot grape marc (MR), raw Sauvignon Blanc grape marc (SbR), Merlot grape marc biorefined (ME) and Sauvignon Blanc grape marc biorefined (SbE). The effects of biosorbent mass and initial Pb concentration, adsorption kinetic, equilibrium isotherms and the matrix influence from a mine effluent were assessed. Very good perspectives for the practical application in lead uptake from wastewaters arise, with better results for biorefined grape marc compared to raw material. The lead removal percentage from an initial solution containing 20 mg Pb/L, at optimum pH (5.5 ± 0.5) was 71%—MR, 78%—SbR, 80%—ME, and 97%—SbE. A Langmuir model revealed a very good removal capacity for ME (40 mg/g) and SbE (64 mg/g). Thus, the grape marc, a polluting waste, can turn into a low-cost and easy-to-prepare sorbent for the bioremediation of contaminated water.