Arsenic adsorption on two types of powdered and beaded coal mine drainage sludge adsorbent.

The aim of this study was to evaluate the performance of a new adsorbent in terms of beading the sludge generated from coal mine drainage or arsenic removed from water is treated by electro-purification (EP) and chemical-precipitation (CP) methods. Batch experiments were conducted to study the influence of experimental parameters such as pH and temperature, as well as the mechanism of arsenic adsorption with the new adsorbent. The porosity of coal mine drainage sludge (CMDS)-beaded adsorbent made of chitosan and alginate was optimized by adding NaHCO 3 powder to generate CO 2 gas during the preparation process. Two types of adsorbents, beaded EP Najeon CMDS (BCMDS EP -NJ) and beaded CP Yeongdong CMDS (BCMDS CP -YD), were prepared by heating. The specific surface areas of the powdered adsorbents CMDS EP -NJ and CMDS CP -YD were 104 and 231 m2 g−1, respectively. The prepared beaded adsorbents BCMDS EP -NJ and BCMDS CP -YD had good porosity and specific surface areas of 16.8 and 21.2 m2 g−1, respectively. The X-ray diffraction results showed that the structure was goethite (aragonite) and schwertmannite. The pseudo second-order, intra-particle, and Langmuir models were used to explain the adsorption process. The q max values of As(III) with BCDMS EP -NJ and BCMDS CP -YD adsorbents are 4.31 and 4.58 mg g−1, respectively and those of AS(V) are 9.31 and 10.93 mg g−1, respectively. The adsorption capacity for As(III) increased with increasing pH, whereas that for As(V) decreased. The activation energy was 8 kJ mol−1 or more. The mechanism of adsorption of arsenic using a beaded adsorbent was chemical adsorption followed by diffusion. The results of the present study suggest that new adsorbents can be effectively utilized for arsenic removal from water. • Synthesis of beaded adsorbent using coal mine drainage sludge and organic binder. • q e and q max induction according to initial pH. • Study on the reaction rate using the synthesized beaded adsorbent. • Confirmation of arsenic chemical adsorption and external diffusion mechanisms. [ABSTRACT FROM AUTHOR]