Biochar-Based Adsorbents for Pesticides, Drugs, Phosphorus, and Heavy Metal Removal from Polluted Water

Water contamination is a ubiquitous issue for all countries and territories worldwide. Among others, pesticides, drugs, heavy metals, and phosphates play a special role in terms of pollutants due to their toxicity and large-scale applications in industrial and agricultural activities. In order to provide cleaner freshwater for the world's population, two types of actions are required: preventing/limiting the pollution that might occur during our daily activities and decontaminating the already exposed/contaminated water sources. One of the key points in the decontamination process is to create as few as possible side effects with the solutions applied. For this reason, in the case of the mentioned types of pollutants but not limited only to them, the use of environmentally friendly materials is more than welcome. Biochar qualifies as one of these materials, and its field of applications expands to larger scientific and industrial areas every day. Moreover, it can be functionalized in order to improve its properties in terms of pollutant removal efficiency. This paper summarizes the most recent developments in the field of water decontamination using biochar or biochar-based materials in order to remove pesticides, drugs, heavy metals, and phosphates from contaminated aqueous environments. Also, the removal of phosphorus from wastewater using biochar is considered. This removal can be a key controlling factor for the wastewater, which is obtained as a residual of agricultural activities. Indeed, due to the excessive use of chemical fertilizers, eutrophication in such kinds of wastewater can be a serious challenge.