活性氧化铝去除煤化工废水氟化物的性能研究

Research on removal performance of fluoride from coal chemical wastewater by activated alumina

为使活性氧化铝更广泛应用于煤化工废水除氟领域,并保证出水氟化物需满足GB 3838—2002《地表水环境质量标准》Ⅲ类水体要求(水氟化物含量降至≤1 mg/L),研究了活性氧化铝对煤化工废水除氟性能的影响。选用1~2 mm活性氧化铝开展连续除氟试验,研究了活性氧化铝装填量、进水pH、吸附时间及停留时间对除氟率的影响,获得出水氟含量降至≤1 mg/L的最佳试验条件;在最佳工艺条件下对活性氧化铝进行实用性考察;并研究了活性氧化铝除氟的反应动力学。结果表明:活性氧化铝装填量越大,除氟率越大,出水氟化物含量越小,活性氧化铝装填量≥60 g时连续吸附40 h后出水氟化物含量仍可维持≤1 mg/L;pH越小,除氟率越大,当pH≤6时连续吸附40 h后出水氟化物含量仍可维持≤1 mg/L;吸附时间越长除氟率越低,吸附时间≤45 h时,出水氟化物含量≤1 mg/L,吸附时间>45 h时,出水氟化物含量>1 mg/L;停留时间越长,除氟率越高,当停留时间6~8 min时连续吸附40 h后出水氟化物含量均≤1 mg/L。当活性氧化铝装填量为60 g,进水pH≤6,停留时间6~8 min,吸附时间≤45 h时,出水氟化物含量可保持在≤1 mg/L;除氟后的活性氧化铝采用硫酸铝再生后重复试验,出水氟含量仍维持在1 mg/L以下,说明活性氧化铝对煤化工废水除氟具有很好的实际应用性;活性氧化铝除氟的反应动力学方程为一级反应,氟含量为3 mg/L时吸附效果最好。

In order to make activated alumina more widely used in the field of coal chemical wastewater defluoridation,and ensure that the fluoride of effluent could meet the requirements of class Ⅲ water body in GB 3838-2002 environmental quality standard for surface water( the fluoride in the effluent is reduced to ≤1 mg/L). The experimental effect of activated alumina on the fluoride removal performance of coal chemical wastewater was studied. The continuous defluorination experiment of activated alumina with particle size of 1-2 mm was carried out. The effects of the dosage,pH value of influent,residence time and adsorption time of activated alumina on the defluorination rate were studied to obtain the best experimental conditions for the fluorine content of coal chemical wastewater effluent to be less than or equal to 1 mg/L. The " practicality" of activated alumina was investigated under the best technological conditions. Finally,the reaction kinetics of activated alumina for removing fluorine was studied. The experimental results show that the larger the activated alumina loading is,the greater the fluoride removal rate is,and the lower the fluoride content in the effluent is. When the loading amount of activated alumina is ≥60 g,the fluoride content in the effluent can still be maintained at ≤1 mg/L after 40 h of continuous adsorption;The smaller pH is,the greater the fluoride removal rate is. When the pH is ≤6,the fluoride content in the effluent can still be maintained at ≤1 mg/L after 40 h of continuous adsorption;The longer the adsorption time is,the lower the fluoride removal rate is. When the adsorption time is ≤45 h,the effluent fluoride content is less than or equal to 1 mg/L and when the adsorption time is more than 45 h,the content of fluoride in the effluent is more than 1 mg/L;The longer the residence time is,the higher the fluoride removal rate is. When the residence time is 6-8 min,the effluent will be continuously adsorbed after 40 h,and the fluoride content is ≤1 mg/L. When the activated alumina loading is 60 g,the influent pH is ≤6,the residence time is 6-8 min,and the adsorption time is ≤45 h,the fluorine content of the outlet water can be kept at≤1 mg/L. The activated alumina after defluorination is regenerated with aluminum sulfate and the experiment is repeated,the effluent fluorine content is still well maintained below 1 mg/L,indicating active oxidation aluminum has a good " practical application" for removing fluoride from coal chemical wastewater. At the same time,the reaction kinetic equation of activated alumina to remove fluoride is a first-order reaction,and the adsorption effect is best when the fluorine content is 3 mg/L.