Critical Parameters and Mechanisms of Chromium Removal from Water by Copper-Based Nanoparticles

Abstract

This research aims to explore the chromium removal from water using copper-based nanoparticles. The nanoparticles were synthesized by hydrothermal method and characterized by X-ray diffraction, scanning electron microscopy, infrared spectroscopy, and X-ray photoelectron spectroscopy as well as determination of the specific surface area (SBET) and point of zero charge (PZC). The size and composition of nanoparticles are influenced by the reaction time, organic coating, and oxidizing atmosphere. Sorption experiments were carried out in aqueous solutions as well as simulated drinking water at various initial concentration, time, and temperature. Cu nanoparticles had a significant Cr uptake capacity of 3.4 mg·g−1 for Cin 1.0 mg·L−1 lowering the Cr concentration below the provisional guideline value of 50 μg·L−1. Sorption isotherms were fitted to Henry, Langmuir, and Freundlich models, whereas kinetic data were reproduced by different kinetic models. Iodide sorption experiments were carried out to explore the sorption mechanism onto Cu-NPs. Considering the biocompatibility, stability, good uptake capacity, and reusability, Cu nanoparticles could be considered as promising agents for applications in water purification.