稻壳生物质炭对水中氨氮的吸附

以稻壳生物质为原材料,在350℃和500℃ 2种温度条件下制备生物质炭(BC350和BC500),采用扫面电镜(SEM)和红外光谱(FTIR)对稻壳生物质炭进行了表征。通过实验考查了稻壳生物质炭对氨氮的吸附等温线、影响因素和动态吸附。结果表明,稻壳生物质炭的平衡吸附量随着平衡浓度的增大而增大后趋缓,Langmuir方程比Freundlich方程更好地描述稻壳生物质炭吸附氨氮的行为,BC500比BC350具有更大的吸附氨氮的能力,其最大吸附量分别为5.82 mg/g和6.51 mg/g。pH和离子强度影响BC500对氨氮的吸附效果。动态吸附实验表明,BC500对氨氮的平均吸附量为1.78 mg/g。可见,稻壳生物质炭可以用作高效吸附剂去除废水中的氨氮。

Adsorption of ammonia nitrogen in wastewater using rice husk derived biochar

The rice husk was used to prepare biochar under 350℃ and 500℃ (designated as BC350 and BC500), and the biochar was characterized by SEM and FTIR. The adsorption isotherms, effect of pH and ion strength on adsorption and dynamic adsorption were also studied. Results indicated that the equilibrium adsorption quantity increased with increasing equilibrium concentration. Langmuir equation fitted the adsorption isotherms better than Freundlich equation and could be used to describe the adsorption behaviors of ammonia nitrogen by the biochar. Biochar had high adsorption capacity for ammonia nitrogen and followed the order: BC500>BC350. The adsorption capacity of ammonia nitrogen predicted by Langmuir equation was 5.82 mg/g and 6.51 mg/g for BC350 and BC500, respectively. pH and ion strength were two factors affecting the ammonia nitrogen adsorption by BC500. Dynamic adsorption experiment showed that the average of ammonia nitrogen adsorption by BC500 reached 1.78 mg/g, all of which indicated that the biochar could be used as an efficient adsorbent to remove the ammonia nitrogen from the wastewater.