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.

Keywords:

• Spent activated carbon
• NaOH regeneration
• Adsorption test
• Iodine number
• Methylene blue number

Acknowledgment

The authors wish to express their gratitude to the School of Environmental Engineering, University Malaysia Perlis (UniMAP) for providing the equipments and technical support during this research.

Notes

Presented at the 2nd IWA Malaysia Young Water Professionals Conference 2015 (YWP15) Aspiring Beyond Water Solution, March 17–20, 2015, Langkawi Island, Malaysia