Abstract: A method of producing biochar from spent coffee grounds, biochar, such as biochar produced according to the methods of the present disclosure, an environmental remediation system including biochar according to embodiments of the present disclosure, and methods of removing contaminants from an aqueous solution using biochar according to embodiments of the present disclosure are described. In an embodiment, the method of producing biochar from spent coffee grounds comprises heating dried spent coffee grounds in an oven in a first pyrolysis temperature range to provide an intermediate biochar; and heating the intermediate biochar and a caustic in the oven in a second pyrolysis temperature range to provide the biochar.