HNO_3氧化改性生物炭吸附水体中阳离子和阴离子染料的影响因素

Influence Factors on Adsorption of Cationic and Anionic Dye from Aqueous Solution by HNO_3-Modified Biochar

以玉米秸秆和甘蔗屑为原料,分别在400℃和800℃制备生物炭并利用HNO_3进行氧化改性。通过分析废水实际处理过程中不同吸附条件对吸附效果的影响,研究了HNO_3氧化改性生物炭对阳离子和阴离子染料的吸附影响因素。结果表明:振荡强度、温度、pH、离子强度、共存离子是影响HNO_3氧化改性生物炭吸附阳离子和阴离子染料的主要因素,且对不同性质染料影响趋势和程度不同。温度高有利于提高HNO_3氧化改性生物炭的吸附作用;未达到吸附饱和前,提高振荡强度促进吸附作用,但达到吸附饱和后高振荡强度不利于吸附作用;高离子强度对HN4GZ吸附阳离子染料有促进作用,中、低离子强度更适合HN4YM和HN8YM对阳离子和阴离子染料的吸附处理;弱酸性条件不利于HN4YM和HN4GZ对阳离子染料的吸附,中性条件不利于HN8YM对阴离子染料的吸附;废水中常见的阳离子/阴离子的存在对两种染料的吸附均有一定负作用,但HNO_3氧化改性生物炭仍表现出令人满意的吸附效果。

Biochar from comstall^ and sugarcane bagasse was produced in 400 ℃ and 800 ℃ and then was modified by HNO3. Analyzing the effects of different adsorption conditions on adsorption,the influence factors on cationic and anionic dye adsorbed by HNO3-modified biochar were researched. Results indicated that oscillation in-tensity ,temperature,pH , ionic strength and coexisting cations/anions were the key factors that can impact adsorp- tion,and their effects on adsorption varied by the characteristics of dye. The positive effect of HNO3-modified bio-char could be found witli increasing temperature. The same tendency was also happened with increasing oscillation intensity before HNO3-modified biochar saturated dye. However,when HNO3-modified biochar saturated dye,high oscillation intensity had adverse effect on adsorption. For ionic strength,there was an increase in the ability of ad-sorption of HN4GZ on cationic dye in high ionic strength,but the adsorption of HN4YM and HN8YM on cationic and anionic dye would be better in mid and lowionic strength than that in high ionic strength. The negative effect of HN4YM,HN4GZ on cationic dye and HN8YM on anionic dye was showed in mild acidic and neutral condition,respectively. In addition,although the coexisting cations/anions had negative effects,the experimental results ap-peared that biochar prepared in this work was still very efective in reclaiming cationic and anionic dye from wastewater.