香蒲基生物炭的活化及对VOCs吸附的应用

以香蒲为原料制备生物炭(Biochar),并用不同试剂进行活化.活化前的Biochar比表面积和孔体积很小,分别为1.71 m^(2)/g和0.00421 cm^(3)/g,而活化后的Biochar比表面积和孔容均增大,其中经碳酸钠(Na_(2)CO_(3))活化后的Biochar比表面积和孔容最大.研究了Na_(2)CO_(3)与Biochar的质量比对其活化的影响,确定了Na_(2)CO_(3)/Biochar最佳质量比为3∶1条件下,得到的样品Biochar-Na_(2)CO_(3)-3具有最优的表面积和孔容,分别为624 m^(2)/g和0.211 cm^(3)/g,并具有优异的挥发性有机化合物(VOCs)吸附性能,其正己烷、甲苯和92号汽油的静态吸附容量分别为1.03,0.814和0.751 g/g,正己烷和甲苯的动态吸附容量分别为1.00和0.796 g/g,且吸附稳定性相对较高,优于商业用活性炭(AC)和硅胶(SG).

Freeze-thaw Effects on Sorption/Desorption of Dissolved Organic Carbon in Wetland Soils

The effects of freeze-thaw cycles on sorption/desorption of dissolved organic carbon （DOC） in two wetland soils and one reclaimed wetland soil were investigated. DOC concentrations added were 0-600 mg/L. Laboratory incubations of sorption/desorption of DOC had been carried out at -15℃ for 10 h, and then at ＋5℃ for 13 h. Soil samples were refrozen and thawed subsequently for 5 cycles. Initial Mass model was used to describe sorption behavior of DOC. The results indicate that freeze-thaw cycles can significantly increase the sorption capacity of DOC and reduce the desorption capacity of DOC in the three soils. The freeze-thaw effects on desorpfion of DOC in soils increase with the increasing freeze-thaw cycles. The conversion of natural wetlands to soybean farmland can decrease the sorption capacity and increase the desorption capacity of DOC in soils. Global warming and reclamation may increase DOC release, and subsequently increase the loss of carbon and the emission of greenhouse gas.

Experimental study on effects of CBM temperature-rising desorption

To study the effects of CBM （coal bed methane） temperature-rising desorption, isothermal adsorption/desorption experiments on three ranks （anthracite, coking coal and lignite） of coal at different temperatures were designed based on the traditional CBM decompression desorption. The experimental results indicate that temperature-rising desorption is more effec- tive in high-rank coal, and ever-increasing temperature of high-rank coal reservoir can reduce the negative effects of coal ma- trix shrinkage in the process of production and improve the permeability of the coal reservoir as well. It is also revealed that the technique of temperature-rising desorption applied in higher-rank coal reservoir can enhance CBM recovery ratio. This study provided theoretical support for the application of temperature-rising desorption technique in practical discharging and mining projects, which can effectively tackle the gas production bottleneck problem.

Comparison of desulfurization kinetics of copper oxide sorbent

Desulfurization experiments of CuO, γ-Al2O3 and CuO/γ-Al2O3 were made in simulated flue gas by means of thermogravimetric analysis. It is found that reaction activities of CuO supported on γ-Al2O3 could be highly improved. Desulfurization kinetics of CuO/γ-Al2O3 was studied in the temperature range of 250 °C-400 °C and SO2 concentration of 0.1%-0.9%. The experimental data were tested and compared with kinetics models of volume reaction model(VRM), grain size model(GSM), random pore model(RPM) and pore-blocking model(PBM). Correlation analysis shows that VRM and RPM models do not fit experimental data well. GSM contradicts with the changes in the physical and chemical properties of Cu O/γ-Al2O3 as the desulfurization proceeds. It is found that PBM is consistent with the change of pore structure of CuO/γ-Al2O3 sorbent during desulfurization process and predicts the conversion-time curves of the sorbent well. Meanwhile, kinetics parameters are obtained and discussed.

Biosorption and desorption of Cd^(2+) from wastewater by dehydrated shreds of Cladophora fascicularis

The adsorption and desorption of algae Cladophora fascicularis and their relation with initial Cd2+ concentration, initial pH, and co-existing ions were studied. Adsorption equilibrium and biosorption kinetics were established from batch experiments. The adsorption equilibrium was adequately described by the Langmuir isotherm, and biosorption kinetics was in pseudo-second order model. The experiment on co-existing ions showed that the biosorption capacity of biomass decreased with an increasing concentration of competing ions. Desorption experiments indicated that EDTA was efficient desorbent for recovery from Cd2+. With high capacities of metal biosorption and desorption, the biomass of Cladophora fascicularis is promising as a cost-effective biosorbent for the removal of Cd2+ from wastewater.

Adsorption and desorption properties of D318 resin for Cr(Ⅵ)

The adsorption capability of D318 resin for Cr（Ⅵ） was investigated by chemistry analysis. Experimental results show that D318 resin has the best adsorption ability for Cr（Ⅵ） at pH=3.16 in HAc-NaAc medium. The statically saturated adsorption capacity of the resin is 265.4 mg/g. The thermodynamic adsorption parameters, enthalpy change AH and free energy change AG298 of the adsorption reaction are 4.81 and -5.16 kJ/mol, respectively. The apparent activation energy Ea is 22.4 kJ/mol. The adsorption behavior obeys the Freundlich isotherm. The molar coordination ratio of the functional group of resin to Cr（Ⅵ） is 3：2. Cr（Ⅵ） adsorbed on D318 resin can be eluted by 5%NaOH-5%NaCl quantitatively.

Adsorption and Desorption of Thiophene Vapor on NaY/NiY Zeolites

FT-IR spectrometry, TPD and adsorption isotherms of thiophene on NaY/NiY zeolites were carried out and the diffusion coefficient was obtained by means of its real-time dynamic curves. The loading of thiophene adsorbed on the NaY zeolite decreased with an increasing temperature, which was ascribed to the patterns of physical adsorption. Both physical and chemical adsorption phenomena were detected on the NiY zeolite, with the 0 complexation and S-M interaction existing during the chemical adsorption. The loading of thiophene adsorbed on the NiY zeolite at 302 K and 335 K was equal, but it decreased at 373 K. The diffusion coefficient of thiophene on the NaY zeolite decreased when the loading increased to more than 0.02 mmol/g, and on the contrary that of thiophene on the NiY zeolite did not change obviously with the loading adsorbed.