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Removal of volatile sulphur compounds from livestock waste air by biological air filtration may be enhanced by application of packing materials with reactive properties. In this study, light expanded clay aggregates (Leca®) was tested with respect to sorption and potential chemical degradation of H2S, Methanethiol (MT) and Dimethyl sulphide (DMS). Leca was selected due to its content of minerals, including iron, and due to its high specific surface area. The performance of Leca was evaluated based on breakthrough curves and by comparing the difference between the inlet and outlet gas concentrations. Whereas DMS did not appear to be removed by Leca, both H2S and MT were removed with variable efficiency depending on the specific conditions. Dimethyl disulphide (DMDS) and dimethyl trisulphide (DMTS) were demonstrated to be produced during the degradation process in relatively high yields. A comparison between ambient air and nitrogen gas conditions showed that the chemisorption of H2S and MT did not necessarily need oxygen to be present. X-ray analysis of Leca showed an abundance of Fe2O3. It is therefore hypothesized that Fe2O3 in Leca can remove H2S and MT by chemisorption. Both air velocity and moisture content clearly affected the capacity of Leca for removal of H2S and MT. Lower removal is seen at higher air velocities, whereas higher moisture content enhances removal. However, chemisorption of MT by Leca appears to be limited above a threshold moisture level. Potential reaction mechanisms are discussed in relation to the observed effects. The results implicate that Leca can be used as a filter material with reactive properties provided that moisture content is controlled and that an adequate air velocity is used. 相似文献
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For the first time, a series of alkynyl carbon materials(ACMs) were prepared via the mechanochemical reaction of CaC_2 with six polyhalogenated precursors, namely CCl_4,C_2Cl_6, C_2Cl_4, C_6Cl_6, C_6Br_6, and C_(14)H_4Br_(10)(ACM-1, ACM-2, ACM-3, ACM-4, ACM-5, and ACM-6,respectively) and used for the adsorptive removal of mercury from aqueous solutions.Based on preliminary investigations, the adsorption of mercury on ACM-5 was studied in depth. Specifically, the effect of p H on mercury adsorptivity, adsorption kinetics,thermodynamics, isotherms, and recyclability was studied. The adsorptivity of mercury on ACMs was found to be closely related to the hydrocarbon precursor, specific surface area of sorbent, and the alkynyl content. ACM-5 showed the best performance and is among the best raw carbonaceous sorbents reported so far, with a Langmuir saturated adsorption capacity of 191.9 mg g~(-1). The promising mercury adsorption performance mainly arises from the strong Lewis soft acid–soft base interactions between the alkynyl groups and mercury ions. The adsorption isotherms could be satisfactorily correlated with the Langmuir equation. The results show that the ACMs can be used as efficient sorbents for the removal of mercury and may also be useful for the adsorption of other heavy metals. 相似文献
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Zhou Zhang Kai Huo Tingxuan Yan Xuwen Liu Maocong Hu Zhenhua Yao Xuguang Liu Tao Ye 《Frontiers of Environmental Science & Engineering》2023,17(8):101
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