阿司匹林生产用废弃活性炭的微波一步再生

阿司匹林生产过程中会产生大量的粉末状废弃活性炭,对环境造成了较大的影响。提出了不外加活化气体的微波加热一步再生法再生废弃活性炭,使之循环利用。通过试验考察了再生温度、再生时间和物料厚度等因素对再生活性炭吸附性能和得率的影响。在再生温度700℃、再生时间10 min和物料厚度20 mm的优化条件下,亚甲基蓝吸附量为180 mg/g,再生活性炭的得率为40.875%,与常规方法再生药用活性炭相比,降低了再生温度,再生时间缩短了50%左右。此时再生活性炭的比表面积为1 296 m~2/g,平均孔径为3.016nm,适合于吸附亚甲基蓝,总孔体积为0.977 4 m L/g,其中微孔占47.81%,表明微孔和中孔都较为发达。扫描电镜和傅里叶变换红外光谱图分析表明,活性炭孔隙和表面性质得到了有效的再生恢复。微波一步再生法避免了通入活化气体而导致大量粉末活性炭被带走的问题,并且该方法具有速度快、效率高等优势。

One-step microwave regeneration method for the recycled use of the forsaken powdered activated carbon in the aspirin production

This paper is to propose a renovated so-called one-step microwave regeneration method for the recycled use of the forsaken powdered activated carbon for the aspirin production.As a matter of fact,the waste activated carbon and regenerated activated carbon still contain fully characterized N2 adsorption and desorption isotherms,which can be identified and isolated through scanning electron microscopy (SEM) and the Fourier transform infrared spectroscopy (FTIR).Therefore,we would like to pursue how to regenerate the waste activated carbon through the microwave heating without adding any activated gas to recycle the waste activated carbon and reduce its pollution as much as possible to the environment.To achieve the purpose,we have to study the effects of the 3 influential factors (namely,regeneration temperature,regeneration time and material thickness) on the adsorption performance and the yield of the regenerated activated carbon.So far as we have got to know,the regenerated activated carbon from the waste can be gained under the optimized conditions at the temperature of 700 ℃,the regeneration time of 10 min and the waste material thickness of 20 mm,under which condition it would be possible to increase the amount of methylene blue absorbed by 180 mg/g with the yield rate being 40.875％.Thus,as compared with the conventional method of regeneration of medicinally activated carbon,it would be possible to reduce the regeneration time by 50％ and the regeneration temperature with the method suggested here.Under the aforementioned conditions,the BET surface area can be increased by 1 296 m2/g with the micropore accounting for 47.81％,with the average pore size increased by 3.016 nm,which is suitable for the methylene blue adsorption.Thus,the analysis of the scanning electron microscope and Fourier transform infrared spectroscopy demonstrates that the pore of the activated carbon and the surface properties have been successfully recovered.Furthermore,the regeneration of activated carbon by using the microwave heating can get rid of large amounts of powder activated carbon due to the activated gas being pumped away.What is more distinguished is that the suggested method is characteristic with high speed and efficiency.The results of the comprehensive experiment prove that the one-step microwave heating method we have developed is feasible for the regeneration of the waste activated carbon.