Removal of cadmium in water by potassium hydroxide activated biochar produced from Enteromorpha prolifera

Cadmium emission from industrial processes is causing serious environmental problems, and biochar adsorption is an effective approach to control the cadmium content in wastewater. Producing biochar from Enteromorpha prolifera could not only provide sustainable biochar resource, but also promisingly solve the algae bloom problem worldwide. This work prepared Enteromorpha prolifera biochar (EPB) via slow pyrolysis method, the effect of different KOH to EPB mass ratios and different influencing parameters were also studied. Characterizations including SEM-EDS, FTIR and elemental analysis were comprehensively conducted to explore the physicochemical properties of EPB. The results showed that EPB activated by KOH with an impregnation ratio of 1:2 had the optimal cadmium removal performance, where a removal efficiency of 99.8% was obtained. Electrostatic interaction was a major adsorption mechanism. The isotherm analysis showed that Langmuir isotherm model could better fit the adsorption data. As a result, KOH activated EPB presented satisfactory features as a promising cadmium adsorbent with multiple environmental benefits.