Activated Clay Prepared by Waste Acid Recycling: Technology and Mechanism

摘要

We determined the optimum activation conditions and formation mechanism of activated clay prepared using anwaste acid recycling method. The aim of this study was to determine the effect of the processes used on thenquality of the activated clay. Key objectives were to optimize operating conditions and to determine thenmechanism of acid treatment. Results of single-factor experiments showed the following optimum conditions:nsulfuric acid concentration of 22%, liquid–solid ratio of 3.5, and 4 h reaction time at 908C. Under these conditions,nthe performance of activated clay appears to be much better than that prepared using the traditional method.nCompared with the traditional method, the waste acid recycling process consumed less sulfuric acid (up to 21%)nand the amount of aluminum released during the activation processes was also lower. Improvement in claynquality was due to the presence of several types of sulfate residue in the waste acid, preventing further dissolutionnof the crystal structure of montmorillonite. This improved structure uniformity resulted in an activatednclay with better performance. Moreover, the waste acid recycle method reduces the environmental impact andnpollution due to acid reuse.