Removal of Phenolic Compounds from Water by Adsorption and Photocatalysis

Abstract

Phenolic compounds are important industrial wastes, and are classified as hazardous substances contaminating groundwater resources. Therefore, the removal or diminish of these organics compounds in order to reach the permitted levels before discharging becomes a challenging. Several processes have been developed to remove phenolic compounds from waters, including electrochemical oxidation, redox reactions, membrane separation and photocatalytic degradation. Recently, tendency of phenolic compounds removal involves adsorption and photocatalytic process, using synthetic or natural particles, such as carbon materials and clays. Actually, materials in nanometric scale play an important role in the processes previously mention due to their unique chemical and physical properties. In this book chapter, the first part shows the chemical properties of phenolic compounds that play an important role in the removal process. In the second part, different materials in macro, micro and nanosize used as adsorbents or photocatalysts are reviewed. In addition, other removal processes of phenolic compounds as electrochemistry and redox reactions are included. The removal conditions in these process, such as pH, adsorbate and adsorbent concentration are analyzed and discussed. Furthermore, special emphasis is included in micro and nanocarbon materials, used as adsorbents or photocatalyst to remove phenol from water in recently researches.

Phenol adsorption on magnetic biochar derived from olive pomace: Equilibrium, kinetic and thermodynamics

“…Adhesives, foams, emulsifiers, detergents, insecticides, dyes, explosives etc., includes phenolic compounds and all these products have economic importance in several industries like food, petrochemical, agriculture etc. [1]. However, phenolic compounds are one of the most important toxic compounds for environment and human health also.…”

Rapid One-Step Fabrication of Graphene Oxide-Decorated Polycaprolactone Three-Dimensional Templates for Water Treatment

“…Among the possible multiple applications of such hybrid materials, in the frame of this work we propose a preliminary study on the suitability of such systems to be adopted as reusable materials for phenol removal from water. In fact, beyond the typical requirements in terms of mechanical robustness, low density, high levels of specific area, and suitable wettability, novel materials for water treatment are required to purify contaminated waters using the lowest possible temperature/energy in order to minimize environmental and economic impact. , In this perspective, materials that provide even full reusability are preferable. , In the case of phenolic compounds, adsorption and photocatalysis are the two most promising technologies with the former one being particularly attractive when coupled with the possibility to easily recover the contaminants in compliance with zero-waste and circular economy concepts. − In this sense, combining the properties of a biodegradable, flexible, recyclable PCL with the well-known GO affinity to phenol molecules might stimulate the fabrication of next generation systems for wastewater treatment.…”

Valorization of wastewater from food industry: moving to a circular bioeconomy

“…The recovery of phenolic-based compounds from agro-food wastewaters is also a very popular valorization process for these effluents, as phenols are among the most discussed categories of natural antioxidants (Galanakis and Kotsiou 2017). Many techniques can be employed for the recovery of phenolic compounds, including solvent extraction, membrane separation (typically using microfiltration, ultrafiltration and nanofiltration membranes in sequence), adsorption (ion exchange on ionic resins or simple adsorption on neutral non-ionic resins), aqueous two-phase systems, thermal processes, reverse osmosis, distillation, and cloud point extraction (Hajji et al 2014;Ramı ´rez et al 2017;Castro-Mun ˜oz et al 2018;Frascari et al 2019b). Adsorption processes using synthetic or natural particles are more commonly used nowadays as the phenolic molecules can be trapped on the surface of the adsorbent material and thus easily separated from the liquid fraction (Ramı ´rez et al 2017).…”