Efficient adsorption removal of Cd~(2+)from aqueous solutions by HNO3 modified bamboo-derived biochar

摘要

In this work porous biochar was prepared from bamboo powder by ZnCl2 chemical activation.The effects of preparation,modification and adsorption conditions on its removal performance of Cd~(2+)in simulated wastewater were investigated by static adsorption.The adsorption kinetics and isotherms of Cd~(2+)were further studied.The results showed that the good adsorption property was obtained over the biochar prepared under optimized preparation and modification conditions.The biochar reached the highest removal efficiency of 95.53% under optimum adsorption conditions.The adsorption process of Cd~(2+)was well in accordance with the pseudo-second adsorption kinetics equation,and the equilibrium adsorption capacity was up to 16.62 mg·g~(-1).The Freundlich isothermal adsorption model better fitted compared with the Langmuir model for this adsorption system and the maximum adsorption capacity was as high as 44.54mg·g~(-1).After four adsorption-desorption recycling,the adsorption removal percentage decreased a little,indicating that biochar had good regeneration performance.In short,this inexpensive porous biochar has the potential to become a practical adsorbent of cadmium.