摘要
以梧桐叶为原料,利用程序升温限氧法分别在350℃、450℃、550℃温度下制备了生物炭(分别记为BC350、BC450、BC550),研究了BC350、BC450、BC550生物炭对染料废水亚甲基蓝的吸附性能.测定了BC350、BC450、BC550生物炭的亚甲基蓝吸附值分别为285 mg·g^-1、435 mg·g^-1、1035 mg·g^-1.研究了BC350、BC450、BC550生物炭对于不同初始质量浓度染料的吸附情况,在室温下,亚甲基蓝初始质量浓度为30~70 mg·L^-1,吸附剂质量浓度为10 g·L^-1,BC550达到吸附平衡的时间均为30 min,去除率均可接近于100%,动力学特征最符合准二级动力学方程,表明此过程以化学吸附为主;Langmuir等温线更符合生物炭吸附亚甲基蓝的过程,表明该过程是单分子层吸附;生物炭对亚甲基蓝的吸附是吸热和熵增过程.扫描电镜图(SEM)、比表面积测定(BET)的表征结果表明,生物炭相比于梧桐叶表面结构发生了明显变化,比表面积也随着炭化温度的升高显著增大,由此提供了更多的吸附位点.梧桐叶生物炭可用作高效吸附剂用来去除亚甲基蓝类的阳离子染料.
With phoenix tree leaves as the raw material,biochar(BC)was produced by sustainable temperature oxygen limited method at three different pyrolysis temperatures(350℃,450℃,550℃),which was referred as BC350,BC450,BC550.The adsorption properties of methylene blue in dye wastewater by BC350,BC450 and BC550 biochar were studied.The methylene blue adsorption values of BC350,BC450 and BC550 biochar were determined,which were 285 mg·g^-1,435 mg·g^-1 and 1035 mg·g-1 respectively.The adsorption of BC350,BC450 and BC550 biochar for dyes with different initial mass concentrations was investigated.At room temperature,the initial mass concentration of methylene blue was 30~70 mg·L^-1,the mass concentration of adsorbent was 10 g·L^-1,and the time when BC550 reached adsorption equilibrium was 30 min,and the removal rate was all close to 100%.The kinetic characteristics are most consistent with the pseudo-second-order equation,which shows that the process is mainly chemical adsorption.The Langmuir isotherm is more in line with the process of biochar adsorption of methylene blue,indicating that the process is single-molecule layer adsorption.The adsorption of methylene blue by biochar is an endothermic and entropy increasing process.The characterization results of scanning electron microscopy(SEM),specific surface area measurement(BET)showed that the surface structure of biochar changed significantly compared to phoenix tree leaves,and the specific surface area also increased significantly with the increase of carbonization temperature,thus providing more adsorption sites.Phoenix tree leaves biochar can be used as a high-efficiency adsorbent to remove cationic dye like methylene blue from wastewater.
作者
钱敏
吴缨
QIAN Min;WU Ying(School of Energy Materials and Chemical Engineering,Hefei University,Hefei 230601,China;School of Chemical Engineering,Hefei University of Technology,Hefei 230009,China)
出处
《安徽化工》
CAS
2020年第4期25-32,37,共9页
Anhui Chemical Industry
基金
安徽省自然科学研究基金后续项目(0391838026)
关键词
生物质炭
亚甲基蓝
吸附
动力学
热力学
biochar
methylene blue
adsorption
kinetics
thermodynamics
