Regeneration of spent activated carbon from industrial application by NaOH solution and hot water

Abstract

Spent activated carbon (SAC) must either be disposed of at a landfill or regenerated and reused in industries. Regeneration of SAC is a more preferable option as it can cut down replacement and disposal cost as well as reduce secondary pollution. Chemical regeneration is more suitable and economically feasible option for small-scale industrial application as compared to thermal regeneration. In this study, SAC is regenerated using sodium hydroxide (NaOH) solution and hot water. The aim of this study is to evaluate the effectiveness of NaOH and hot water regeneration of SAC. The optimal regeneration condition for SAC was determined and the regeneration performance was assessed by iodine and methylene blue (MB) adsorption test. Finding shows the optimal regeneration condition of carbon regeneration is 15 mL of 6 N of NaOH solution per g of carbon with 30 min of contact time. The estimated surface area, micropore volume, and total pore volume of batch and column regenerated SAC were 899.1 m2/g, 0.8702 cm3/g, 0.9521 cm3/g; and 849.0 m2/g, 0.8519 cm3/g, and 0.9450 cm3/g, respectively. The regeneration efficiency of regenerated SAC is comparable to fresh activated carbon with regeneration efficiency more than 90% in iodine adsorption test and 98% in MB adsorption test.