Facile fabrication of flexible super hydrophilic activated carbon sponge for continuous capillary adsorption

Abstract

Activated carbon powder was fixed using calcium alginate into a melamine-formaldehyde sponge to separate organics from water and wastewaters easily. The specific surface area and the mean pore size of the adsorbent were obtained as 354.3 m2/g and 2.63 nm, respectively. The contact angle of the AC-sponge was ~0° due to complete and rapid absorption of water droplets indicating its super hydrophilic property. The adsorption isotherm model was well represented by both Langmuir and Freundlich equations. The kinetic equations followed pseudo-second-order models for the adsorption of methylene blue as an indicator. Continuous treatment was investigated in a novel capillary adsorption system. It is a simple, efficient, and energy-saving method. Water was passed through a strip of the sponge from one side to the other side by the capillary action and the difference in water level between the two sides. The system was operated at initial MB concentration of 10 and 50 mg/L, and flow rate of 0.75 and 1.5 mL/min. The results showed easy water flow inside the super hydrophilic sponge and long breakpoint times. The breakpoint time was 2476 min at 10 mg/L initial MB concentration and 0.75 mL/min flow rate. Further, about a 30 % increase in the breakpoint time was observed due to pause times during the operation. The regeneration of the adsorbent was still up to 92.5 % after the second regeneration.