活化时间对加氢半焦气化废水吸附性能的影响

Effect of Activation Time on Performance of Hydrogenation Char for Adsorption of Gasification Wastewater

以加氢半焦为原料,利用下落床和固定床装置,高温水蒸气活化直接制得廉价的活性焦,并对其进行高浓度和低浓度气化废水处理实验.在优化的制备条件下,分别考察了活化时间对活性焦吸附指标和废水吸附性能的影响.结果表明:随着活化时间由5s增加到120min,所制备活性焦的苯酚吸附值和碘值先增加后略微下降,总比表面和总孔容增加.未活化的加氢半焦吸附指标较低且废水吸附效果较差.采用下落床活化,活化时间为5s时,活性焦吸附性能提高不明显;而采用固定床活化,活性焦吸附性能明显提高.当活化时间为90min时,活性焦的苯酚吸附值和碘值达到最大值,分别为97mg/L和588mg/L,总比表面积和总孔容分别可达675.53m2/g和0.631 2cm3/g.当活化时间>30min时,自制活性焦对高低浓度气化废水中COD、总磷、TOC的去除率和吸附容量与市售活性焦相近,而活化时间在30min^120min范围内变动导致COD、总磷、TOC的去除率和吸附容量变化范围均<5%,活化时间对高低浓度气化废水中COD、总磷、TOC的去除率和吸附容量均影响不大.

Cheap activated coke was directly prepared by using drop-tube reactor and fixed bed reactor under optimum preparation condition with high temperature steam activated method from hydrogenation char,and was used as adsorbent to treat high and low concentration gasification wastewater.The results show that with increasing activation time from 5 sto 120 min,the adsorption for iodine and phenol adsorbance of activated coke both first increase and then decrease slightly,while the specific surface and total pore volume of activated coke increase.Hydrogenation char without activation has poor performance both in adsorption index and treatment for wastewater.Activated coke prepared by using drop-tube reactor with activation time of5 shas not obvious change in adsorption properties,while adsorption properties of activated coke prepared by using fixed bed reactor increase obviously.When activation time is 90 min,the adsorption for iodine and phenol of activated coke reaches the highest,97 mg/L and 588 mg/L respectively,and the specific surface and total pore volume of activated coke reach 675.53 m2/g and 0.631 2 cm3/g respectively.When activation time is more than 30 min,the activated coke has good performance on the removal rate and absorption capacity of COD,phosphorus and TOC,similar to commercially available activated coke,while with the activation time changing from 30 min to 120 min,the variation range of removal rate and absorption capacity of COD,phosphorus and TOC are less than 5%,the activation time has little influence on the removal rate and absorption capacity of COD,phosphorus and TOC.