微波辐照废木屑活性炭制备工艺优化及其应用

Optimization of activated carbons production from waste sawdust via microwave heating and its application

以微波为热源,Na2CO3为活化剂,采用化学活化法制备废木屑活性炭(AC)。采用Taguchi法考察了微波辐照功率、辐照时间、活化剂浓度、固液比对活性炭碘吸附值的影响。结果表明,微波辐照功率对活性炭碘吸附值的影响最显著,辐照时间次之,而固液比的影响不显著。优化的工艺参数为微波辐照功率440 W、辐照时间9 min、Na2CO3浓度15%、固液比1∶2.5,该条件下AC的碘吸附值为1 230.40 mg/g,实验结果验证了Taguchi法的有效性。该条件下制得的AC用于处理印染废水,结果显示,对COD为239.5 mg/L废水投加3 g/L活性炭,在pH为11时吸附70 min,COD的去除率达77.9%。

Microwave was used as a heat source in preparing activated carbon （AC） from waste sawdust by Na2CO3 chemical activation in this study. Taguchi method was used to investigate effects of microwave power, microwave radiation time, Na2CO3 solution concentration and solid-to-liquid ratios on iodine value. Results re- vealed that microwave power was the most important factor, followed by radiation time. However, solid-to-liquid ratios had no significant effect. The optimized technological parameters were as follows： microwave power of 440 W, microwave radiation time of 9 rain, Na2 CO3 solution concentration of 15 % and solid-to-liquid ratios of 1：2.5, iodine value was up to 1 230.40 mg/g. Adequacy of model equation for predicting optimal response values was verified effectively by validation. Furthermore, the prepared AC was applied to wastewater treatment, and results showed that, with 3 g/L mass fraction addition of AC, the COD removal rate of wastewater was 77.9% after 70 min adsorption at pH 11.