Facile one-step synthesis of functionalized biochar from sustainable prolifera-green-tide source for enhanced adsorption of copper ions.The use of biochars formed by hydrothermal carbonization for the treatment of contaminated water has been greatly limited, due to their poorly developed porosity and low content of surface functional groups.  Hence, the objective of this research was to produce a cost-effective biochar with improved performance for the treatment of heavy metal pollution through a facile one-step hydrothermal carbonization process coupled with ammonium phosphate, thiocarbamide, ammonium chloride or urea, without any post-treatment.  The effects of various operational parameters, including type of modification reagent, time and temperature of hydrothermal treatment, and ratio of modification reagent to precursor during impregnation, on the copper ion adsorption were examined.  The adsorption data fit the Langmuir adsorption isotherm model quite well. 
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