Adsorption is the most preferred method for removing contaminants from water bodies out of all the available water treatment technologies. Numerous studies have been conducted recently to look at using biochar produced by pyrolysis to eliminate pollutants from solutions that are aqueous in nature. Given the abundance of feedstock, relatively inexpensiveness, and advantageous physical surface properties, biochar has considerable potential to effectively combat water contaminants. Biochar is a heterogenous carbon-containing char produced by thermally heating significant amounts of totally degraded organic waste biomass like crop residues, forest biomass, algae, and animal manures. Yet, there is a dearth of knowledge on the functions of various sorption mechanisms for various contaminants, and the latest developments in biochar modification to attain an effective adsorption capacity that is essential for the forthcoming prospects of biochar. This chapter aims to explain the several kinds of biochar that can be used to efficiently remove heavy metals, ions, organic compounds, and dyes from wastewater as well as the ideal conditions needed for the optimal removal of the contaminants. The objective is to give a detailed summary in the use of biochar as a cost-effective and sustainable adsorbent to get rid of harmful substances from aqueous environments and to draw attention to the need for further research in this intriguing area of bioremediation that could be used in wastewater treatment projects in the future.