Towards sustainable physiochemical and biological techniques for the remediation of phenol from wastewater: A review on current applications and removal mechanisms

Phenol is a priority pollutant that presents a significant threat to human health and natural systems when discharged directly into the environment. Consequently, numerous technologies have been used and developed to eliminate phenol from wastewater streams. These technologies can be categorized into physical, chemical, and biological methods. While conventional treatment methods are highly efficient in phenol removal; some of these techniques are not environmentally friendly and others are expensive. Therefore, sustainable, and green technologies are being employed and taken into consideration in the treatment of phenol wastewater due to their effectiveness, affordability, and environmental compatibility. This review aims to highlight efficient green physiochemical and biological methods of water treatment and demonstrate the mechanisms of phenol removal in these technologies. Particular emphasis will be given to the use of low-cost adsorbents prepared from industrial and agricultural wastes for the efficient removal of phenol from wastewater as adsorption processes show the highest cost-effectiveness among all the treatment technologies.