杨木炭对东北黑土吸附猪粪沼液氮素特性的影响

为探究杨木炭对东北黑土吸附猪粪沼液氮素特性的影响,明晰其吸附机理,选取杨木炭和壤质、砂质两种黑土,以活性炭作为标准比较炭,系统研究活性炭、杨木炭的粒径及添加比例、初始质量浓度、振荡时间、温度对黑土吸附、解吸猪粪沼液中氨态氮、硝态氮特性的影响规律,并拟合等温吸附模型和吸附动力学模型。结果表明:黑土对猪粪沼液氮素的吸附能力随着活性炭和杨木炭粒径的减小、添加比例的增加而显著增加;当粒径为0.25 mm、添加比例10%时,添加杨木炭的黑壤土和黑砂土的氨态氮、硝态氮的吸附量为224.8、107 mg/kg和212.4、104 mg/kg,比空白纯黑壤土和黑砂土提高388.7%、296.3%和453.13%、333.33%,比添加活性炭的黑壤土和黑砂土降低19.71%、10.08%和12.38%、7.14%,但添加杨木炭比添加活性炭对吸附平衡后沼液中氨态氮、硝态氮浓度变化影响的差异均不超过2.5%;添加活性炭黑土、杨木炭黑土、空白纯黑土和纯炭对猪粪沼液中氨态氮的吸附过程为吸热反应,而对硝态氮的吸附过程为放热反应,且所有吸附过程均经历快速、缓慢、趋于平衡3个阶段,硝态氮快速吸附的时间更短;Freundlich、Langmuir模型和准二级模型均能较好描述其等温吸附过程和吸附动力学过程,Freundlich模型比Langmuir模型相对更优,吸附反应过程同时存在不均匀的多分子层表面物理吸附和均匀的单分子层化学吸附;添加活性炭、杨木炭黑土对沼液中氨态氮、硝态氮的吸附量越大,解吸率也越大,但解吸量远小于有效吸附量,添加杨木炭的黑壤土和黑砂土对氨态氮、硝态氮的有效吸附量比添加活性炭的黑壤土和黑砂土减少14.57%、9.19%和5.34%、5.74%。杨木炭在提高黑土对猪粪沼液氮素的吸附能力、减少猪粪沼液氮素损失方面的效果优良,可为杨木炭和猪粪沼液在东北黑土改良方面的深入研究提供理论依据。

Kinetic and Thermodynamic Studies of Acid Scarlet 3R Adsorption onto Low-cost Adsorbent Developed from Sludge and Straw

A low-cost adsorbent was prepared from sludge and straw by pyrolysis in a dried state with the surface area of the adsorbent of 829.49 ma. g-l, micropore volume of 0.176 cm2·g-1 and average pore radius of 5.0 nm. The kinetic, equilibrium isotherm and thermodynamic characteristics of trisodium 1-（1-naphthylazo）-2-hydroxynaphthalene- 4＇,6,8-trisulphonate （acid scarlet 3R） onto the adsorbent from sludge and straw were investigated. The results indicated that the pseudo second order adsorption was the predominant adsorption mechanism of acid scarlet 3R. Thus, the adsorption phenomenon was suggested as a chemical process. The adsorption data were fitted better with Langmuir model than Freundlich model, indicating that the adsorption of acid scarlet 3R belonged to the monolayer adsorption and mainly occurred in micropores.

Effects of Non-specific and Specific Solvation on Adsorption of BPTI on Au Surface： Insight from Molecular Dynamics Simulation

Proteins adsorption at solid surfaces are of paramount important for many natural processes. However, the role of specific water in influencing the adsorption process has not been well understood. We used molecular dynamics simulation to study the adsorption of BPTI on Au surface in three water environments （dielectric constant model, partial and full solvation models）. The result shows that a fast and strong adsorption can occur in the dielectric environment, which leads to significant structure changes, as confirmed by great deviation from the crystal structure, largely spreading along the Au surface, rapid lose in all secondary structures and the great number of atoms in contact with the surface. Compared to the dielectric model, slower adsorption and fewer changes in the calculated properties above are observed in the partial solvation system since the specific water layer weakens the adsorption effects. However, in the partial solvation system, the adsorption of polar Au surface causes a significant decrease in the specific hydration around the protein, which still results in large structure changes similar to the dielectric system, but with much less adsorption extent. Enough water molecules in the full solvation system could allow the protein to rotate, and to large extent preserve the protein native structure, thus leading to the slowest and weakest adsorption. On the whole, the effects of non-specific and specific solvation on the protein structure and adsorption dynamics are significantly different, highlighting the importance of the specific water molecule in the protein adsorption.

大孔树脂纯化核桃隔膜总黄酮的工艺研究

目的研究核桃隔膜总黄酮的大孔树脂纯化工艺。方法通过对12种不同型号大孔树脂进行静态吸附与解吸实验,优选适宜的大孔树脂,并优化分离纯化条件。结果 AB-8型大孔树脂对核桃隔膜总黄酮有较好的吸附和洗脱效果,其最佳分离纯化条件为pH 4.70,0.713 5 mg/mL的质量浓度上样,树脂的上样量为4 mL/g,上样体积流量为1.5 BV/h,依次用2 BV水洗脱,2.5 BV 50%乙醇洗脱。经AB-8树脂处理后的总黄酮质量分数达72.25%,收率为93.94%。结论 AB-8型大孔树脂用于富集核桃隔膜总黄酮效果最佳,是一种理想的分离纯化介质。

大孔树脂纯化胡柚皮总黄酮的工艺研究

目的研究胡柚皮总黄酮的大孔树脂纯化工艺。方法通过对8种不同型号大孔树脂进行静态吸附与解吸实验,优选合适的大孔树脂,并优化分离纯化条件。结果 HPD-300型大孔树脂对胡柚皮总黄酮有较好的吸附和洗脱效果,其最佳分离纯化条件如下:pH 4.0,3.83 mg·m L^(-1)上样液,上样量为5 m L·g^(-1),上样体积流量为2.0 BV·h^(-1),依次用2 BV的水洗脱,4 BV 70%乙醇洗脱,洗脱剂的流速为2 BV·h^(-1)。经HPD-300树脂处理后的总黄酮质量分数达76.21%,收率为93.94%。结论 HPD-300型大孔树脂用于富集胡柚皮总黄酮效果最佳,是一种理想的分离纯化介质。

Selective adsorption of metronidazole on conjugated microporous polymers

Conjugated microporous polymers(CMPs) have recently received extensive attention in oil/organic solvent-water separation field as a kind of ideal porous absorbents with tunable porosity, large surface areas, and super-hydrophobicity. However, reports on the application of CMPs in adsorption of hydrophilic contaminants from water are very few. In this work, we studied the adsorption of metronidazole(MNZ), a polar antibiotic, by two kinds of CMPs. The adsorption characteristics of MNZ by the CMPs, including adsorption kinetics, mechanism, and isotherm parameters were calculated. The adsorption kinetics of MNZ was well expressed by the pseudo-second-order model, and the adsorption process was found to be mainly controlled by film diffusion. The adsorption isotherm data agreed well with the Langmuir isotherm model, and the values of free energy E indicated that the adsorption nature of MNZ on the CMPs was physisorption. Increasing dispersion degree of the CMPs in MNZ solution resulted in greater adsorption. This work may provide fundamental guidance for the removal of antibiotics by CMPs.