摘要
生物炭在修复污染土壤、持留土壤养分和促进农作物增产等方面的应用日益得到重视,被认为是未来的一种新型的环境和农业功能材料。本试验以米糠和麦麸为原料,研究了不同热解温度下(300～700℃)制备的生物炭理化性质的变化及对硒等温吸附的影响。结果表明:米糠与麦麸的炭化率随着温度的升高而降低;在300～550℃,pH随着温度的升高先升高,进一步增加温度变化不显著;电导值(EC)随着温度的升高先升高而后下降;生物炭比表面积(BET)随着温度的升高呈增加的趋势。SEM图谱显示炭化米糠及麦麸是成碎片化的状态。红外测定图谱(FTIR)显示随着热解温度的升高,米糠及麦麸的官能团逐渐减少。热重分析(TG-DTG)图显示米糠及麦麸的热解温度主要集中在300℃左右。炭化米糠和麦麸在低硒浓度下(0～50mg·L^(-1))对硒的吸附量随着溶液中硒浓度的升高逐渐增大,当浓度进一步增大时(50～300mg·L^(-1)),生物炭吸附硒的吸附量趋于平衡。通过Langmuir和Freundlich模型拟合比较发现米糠和麦麸生物炭的硒吸附近似单分子层吸附,并且对硒均具有有效的吸附能力,炭化米糠和炭化麦麸均在700℃具有最大吸附量,分别为49.2和54.7mg·g-1。表明炭化麦麸对硒的吸附效果整体优于炭化米糠对硒的吸附效果。
The application of biochar in remediation of contaminated soil,retaining soil nutrients and promoting crop yield has been paid more and more attention.Biochar is considered as a new environmental and agricultural functional material in the future.This experiment was to study the physicochemical properties of biochars prepared using rice bran and wheat bran at different temperatures （300-700 ℃） and its effects on selenium isothermal adsorption.The results showed that the carbonization ratios of rice bran and wheat bran decreased with increasing temperature,the pH value increased with increases in temperature from 300 to 550 ℃,but did not change with further increases in temperature to 700 ℃.The EC value increased and then decreased with increasing pyrolysis temperature.The BET of rice bran biochars increased and then decreased with increasing temperature.The BET of wheat bran biochars gradually increased with increase in temperature.The SEM spectra showed that the carbonized rice bran and wheat bran were fragmented.The infrared spectrum indicated that the functional groups of rice bran and wheat bran biochars decreased gradually with the increase in pyrolysis temperature.TG-DTG diagram showed that the pyrolysis temperature of rice bran and wheat bran is mainly around 300 ℃.Under low selenium concentration （0-50 mg ·L -1 ）,the adsorption of selenium on carbonized rice bran and wheat bran increased gradually with the increase of selenium concentration in the solution.When the concentration increased further （50-300 mg ·L -1 ）,the adsorption of selenium on biochar tended to balance.The fitting of Langmuir and Freundlich models showed that the adsorption of rice bran and wheat bran biochars for selenium belongs to monolayer adsorption.In addition,rice bran and wheat bran biochars have an effective adsorption capacity for selenium.Rice bran and wheat bran biochars have 49.2 and 54.7 mg ·L -1 of the maximum adsorption capacity at 700 ℃,respectively.The adsorption effect of carbonized wheat bran on selenium is better than that of carbonized rice bran.
作者
李玉奇
李磊
朱艳
冯冰
薛思寒
占丹
LI Yu-qi;LI Lei;ZHU Yan;FENG Bing;XUE Si-han;ZHAN Dan(School of Chemical Engineering and Food Science,Hubei University of Arts and Science,Xiangyang 441053 China)
出处
《黑龙江农业科学》
2018年第11期32-37,共6页
Heilongjiang Agricultural Sciences
基金
湖北省自然科学基金面上资助项目(2017CFB608)
中央引导地方科技发展专项资助项目(鄂财教发[2016]109号)
襄阳市科技研究与开发一般资助项目(襄科计[2017]10号)
关键词
热解温度
米糠
麦麸
生物炭
硒
吸附
pyrolysis temperature
rice bran
wheat bran
biochar
selenium
adsorption
