Zhao Baowei, Xu Huan, Ma Fengfeng, Zhang Tao, Nan Xujun
School of Environmental and Municipal Engineering, Lanzhou Jiaotong University No. 88, West Anning Road Lanzhou 730070 Gansu P. R. China
RSC Adv. 2019 Feb 12;9(9):5218-5223. doi: 10.1039/c8ra08916g. eCollection 2019 Feb 5.
The adsorption of nitrogen and phosphorous nutrients on biochar and even biochar-soil mixtures was investigated. However, the situation of sulfur was not very clear. Here, sulfate (SO ) adsorption onto dairy manure biochar obtained at 700 °C (DMBC700), soil (light sierozem) and a 1 : 9 (w/w) biochar-soil mixture (DMBC700-soil) was investigated using batch experiments. The contact time, sulfate concentration, and solution pH value were chosen as the main factors; their effects on sulfate adsorption were tested, and the kinetics and isotherms were also investigated. Fourier transform infrared (FTIR) and X-ray diffraction (XRD) spectroscopies were used to characterize DMBC700 and soil before and after adsorbing sulfate, respectively, and to analyze the mechanisms of adsorption. The results showed that the adsorption kinetics were well described by the pseudo-second-order model, whereas the Langmuir and Freundlich models fitted well with the equilibrium data. DMBC700 modification did not increase the adsorption capacity of light sierozem for sulfate. When the pH values of the initial solution were increased, all the adsorption capacities of sulfate onto DMBC700, light sierozem and light sierozem with DMBC700 decreased. The electrostatic interaction was the main force for the adsorption of sulfate onto DMBC700, whereas both electrostatic interaction and formation of poorly soluble CaSO were the main forces for adsorption of sulfate onto light sierozem. DMBC700 was found to have negative effect on sulfate adsorption onto light sierozem.
研究了生物炭甚至生物炭 - 土壤混合物对氮和磷养分的吸附情况。然而，硫的情况尚不清楚。在此，采用批量实验研究了700°C下获得的奶牛粪便生物炭（DMBC700）、土壤（轻质灰钙土）以及1:9（w/w）生物炭 - 土壤混合物（DMBC700 - 土壤）对硫酸盐（SO ）的吸附。选择接触时间、硫酸盐浓度和溶液pH值作为主要因素；测试它们对硫酸盐吸附的影响，并研究吸附动力学和等温线。分别使用傅里叶变换红外光谱（FTIR）和X射线衍射光谱（XRD）对吸附硫酸盐前后的DMBC700和土壤进行表征，并分析吸附机制。结果表明，吸附动力学可用准二级模型很好地描述，而Langmuir和Freundlich模型与平衡数据拟合良好。DMBC700改性并未提高轻质灰钙土对硫酸盐的吸附能力。当初始溶液的pH值升高时，DMBC700、轻质灰钙土以及含DMBC700的轻质灰钙土对硫酸盐的吸附能力均下降。静电相互作用是硫酸盐吸附到DMBC700上的主要作用力，而静电相互作用和难溶性CaSO的形成是硫酸盐吸附到轻质灰钙土上的主要作用力。发现DMBC700对轻质灰钙土吸附硫酸盐有负面影响。
