Preparation of a Hybrid Membrane from Whey Protein Fibrils and Activated Carbon to Remove Mercury and Chromium from Water

Laura Cristina Ramírez-Rodríguez,Carlos Jiménez-Junca,Adrián Bonilla-Petriciolet,María Ximena Quintanilla-Carvajal,Luis Eduardo Díaz Barrera,Didilia Ileana Mendoza-Castillo

doi:10.3390/membranes10120386

Abstract

Water contamination by mercury and chromium has a direct effect in human health. A promising technology to remove heavy metals by membrane filtration is the use of hybrid membranes produced with whey protein fibrils (WPF) and activated carbon (AC). In this study, the best conditions to produce WPF by heat treatment were determined to maximize the removal of mercury and chromium from water using a central composed design. The results indicated that the best conditions to prepare WPF were 74 °C, 7 h and 3.8% of whey protein with adsorption capacities of 25 and 18 mg/g and removal efficiencies of 81 and 57% for mercury and chromium, respectively. WPF and AC were used to prepare a hybrid membrane that was characterized using transmission electron microscopy, atomic force microscopy, scanning electron microscopy, Fourier transform infrared spectroscopy and Brunauer–Emmett–Teller surface area measurements. Batch filtration experiments were performed with the hybrid membrane for chromium and mercury removal at 25, 50 and 100 mg/L to determine its adsorption capacities. A high performance of the hybrid membrane was demonstrated removing efficiently mercury and chromium from water, thus supporting more than ten filtration cycles.

Highlights

Water pollution affects millions of people around the world, which leads to health problems and can cause death in populations under extreme conditions [1]
analysis of variance (ANOVA) indicated that all tested parameters of whey protein fibrils (WPF) production had a significant effect (p < 0.05) on the adsorption capacity and efficiency for mercury, while the quadratic term associated to the temperature in the model given by Equation (1) was not significant
It has been demonstrated that the operational conditions to produce WPF as temperature, time and whey content have a critical effect on whey protein aggregation and, on the adsorption capacity of heavy metals

Summary

Introduction

Water pollution affects millions of people around the world, which leads to health problems and can cause death in populations under extreme conditions [1]. The major sources of water pollution by toxic ions are unregulated industries, energy production and mining, which have substantially increased the pollutants concentration in water [2]. Heavy metal ions are not biodegradable and have a massive effect in the ecosystem. As a result, their bioaccumulation and biomagnification are present in organisms and the food chain [3]. Heavy metals cause serious health risks and environmental impacts [4].

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Conclusion