Current Perspectives on the Sustainable Remediation of Lead-Contaminated Water Using Tomato Juice By-Products

The large quantities of agri-food waste produced worldwide by the tomato processing industry require recovery. This study evaluated the efficiency of the by-product resulting from tomato juice preparation as an innovative biomaterial for removing lead from water. The pomace was dried and tested in two forms: raw (RT) and after extraction of soluble compounds (ET). The extracts obtained from the preparation of ET, could be reintroduced into the food industry (as colorants, etc.) according to the “zero waste” principle, but further studies are needed. No other chemical pre-treatment was applied to improve the lead-adsorption capacity. The pH influence, biosorbent dosage, kinetics and equilibrium were evaluated. Analytical methods, such as atomic absorption spectrometry, elemental chemical analysis, FTIR, scanning electron microscopy, and predictive models, were applied. The outcomes demonstrated a lead-adsorption efficiency of 99.22% for ET and 89.83% for RT, an optimum pH of 4.0 ± 0.5, and an initial solution containing 20 mg Pb2+/L. The Langmuir model predicted high removal capacities: 142.18 mg/g for ET and 90.91 mg/g for RT. Both forms of tomato pomace were efficient for sustainable and cost-effective water remediation, but an improvement was noticed after the extraction of soluble components that could be valorized in other products within the circular economy.