负载镧镁活性氧化铝的制备及除氟性能研究

采用浸渍法制备负载镧镁活性氧化铝改性除氟剂,用于去除溶液中氟离子。通过正交实验考察镧镁摩尔比、焙烧温度和焙烧时间对改性活性氧化铝吸附性能的影响,得出最佳合成条件为镧、镁物质的量比1∶2,焙烧温度300℃,焙烧时间2.0 h。研究吸附时间、投加量、p H值和共存阴离子对氟离子吸附效果的影响。结果表明:吸附时间为3.0 h、投加量为3.6 mg/L,p H值在6~9,除氟效果最好,氟离子去除率为94.5%;对比不同阴离子对除氟性能的影响,除氟性能受阴离子影响力大小为:CO2-3>SO2-4>Cl->NO-3;吸附剂对氟离子的吸附过程符合伪二级动力学模型,吸附等温线满足Langmuir吸附等温式,其饱和吸附量为7.663 mg/g;不同温度下的热力学结果表明该反应为自发吸热反应。

RESEARCH ON PREPARATION AND FLUORIDE REMOVAL PERFORMANCE OF LANTHANUM-MAGNESIUM-LOADED ACTIVATED ALUMINA

Lanthanum-Magnesium-loaded activated alumina prepared through impregnation was used to remove fluoride fromaqueous solution． By orthogonal experiment，the paper studied effect of absorbability with La3 + /Mg2 + molar ratio，calcinationtemperature and calcination time． The optimum conditions were as follows: The molar ratio of La3 + to Mg2 + was 1 ∶ 2，thecalcination temperature was 300 ℃，the calcination time was 2. 0 h． The influence of contact time，absorbent dosage，pH，and coexisted negative ions on fluoride adsorption were performed． Results showed that the optimum effect was contact time of3. 0 h，absorbent dosage of 3. 6 mg /L，pH of 6 ～ 9， and the removal rate was 94. 5%． The influence of different anions on theadsorption was: CO2 －3 ＞ SO2 －4 ＞ Cl － ＞ NO －3 ． Kinetic data were well described by the pseudo-second-order kinetic model． Theadsorption isotherm could be well fitted by the Langmuir equation． The max adsorption capacity was 7. 663 mg /g． The resultsdemonstrated that the adsorption process was spontaneous and endothermic．