Mohsen Nowrouzi

We studied the applicability of advanced counter-current procedure to convert waste tissue to a highly porous activated carbon (AC) in a zero liquid discharge (ZLD) process with a minimum consumption of the KOH activating agent. AC with a maximum surface area of 1820 m2/g was synthesized by a twostep process, including carbonization at 500
C for 1 h and KOH activation (ratio: 1–3 w/w) at 750
C for 1 h. The water in the washing step containing residual KOH was recycled to the carbonization step for successive cycles. The recycling process continued to reach a steady-state condition. Various techniques including XRD, FTIR, TGA, BET and SEM were utilized to compare the characteristics of the AC synthesized during 10 consecutive liquid recycling steps. The results showed that KOH usage was decreased by 99% and the water requisition per cycle was limited to the make-up water to compensate for the water loss due to evaporation. The product characteristics were found entirely similar to the product obtained with fresh water and KOH. The results of this research can be considered as a promising approach for the synthesis of high product quality sorbent for the eco-environmental applications.