【目的】明确非离子表面活性剂对土壤结构性质及水流运动特征的影响。【方法】基于室内土柱灌溉试验,研究不同灌溉水非离子表面活性剂浓度(0、0.02、0.05和0.10倍临界胶束浓度)、不同灌水频率(1 d 1次、2 d 1次、3 d 1次)、不同灌溉模式...【目的】明确非离子表面活性剂对土壤结构性质及水流运动特征的影响。【方法】基于室内土柱灌溉试验,研究不同灌溉水非离子表面活性剂浓度(0、0.02、0.05和0.10倍临界胶束浓度)、不同灌水频率(1 d 1次、2 d 1次、3 d 1次)、不同灌溉模式(纯清水灌溉、纯再生水灌溉、再生水-清水交替灌溉)条件下的土壤团聚体稳定性、体积质量、孔隙结构、土壤滴水穿透时间、灌水入渗时间和土壤水流运动非均匀程度的变化规律。【结果】非离子表面活性剂有利于提升土壤团聚体稳定性和土壤特征孔隙率、降低土壤体积质量,但也增大了土壤斥水性和水流运动的不确定性;低频率、高定额的灌水方式加剧了土壤团聚体的崩解,高频率、低定额的灌水方式增大了土壤水流运动的非均匀性;含非离子表面活性剂的灌溉水和清水交替灌溉模式具有提升土壤团聚体稳定性、增大土壤孔隙率,同时降低土壤斥水性和水流运动不确定性的优势。【结论】再生水农田灌溉宜采用再生水和清水交替灌溉模式,以平衡非离子表面活性剂对土壤的积极作用与潜在负面影响。展开更多
Cationic Gemini surfactants, alkanediyl-α ,ω- bis(dimethyl dodecylammonium bromide) have been synthesized by the following method: firstly dodecyl bromide was prepared by the reaction of dodecanol with bromic acid i...Cationic Gemini surfactants, alkanediyl-α ,ω- bis(dimethyl dodecylammonium bromide) have been synthesized by the following method: firstly dodecyl bromide was prepared by the reaction of dodecanol with bromic acid in the presence of strong sulfuric acid. Dodecylbromide was then reacted with N,N- tetramethyl ethane diamine(or N,N- tetramethyl hexana diamine) to prepare the title- compounds. Micellization of these Gemini surfactants was investigated using conductivity measurement. The results showed that the critical micelle concentration(cmc) of the Gemini surfactants has a much lower value compared with that of the corresponding " monomer" . For a series of the Geminis with the same length(s) in the spacer chain, the cmc decreased with increasing the carbon number (m) in the alkyl chain. The aggregation number(N) of the micelle also drastically decreased with m. For the same value of m, the cmc varied slightly with s, which indicated that the electrostatic interaction between the ionic- groups of the " monomer" has been naturally changed duo to a link between the two ionic- groups of the " monomer" through a spacer. However, N was strongly decreased with s,which may be a reason of steric inhibition coming from the ionic- groups due to a link of spacer. With increasing temperature, micellization of the Gemini surfactants was slightly enhanced.展开更多
文摘【目的】明确非离子表面活性剂对土壤结构性质及水流运动特征的影响。【方法】基于室内土柱灌溉试验,研究不同灌溉水非离子表面活性剂浓度(0、0.02、0.05和0.10倍临界胶束浓度)、不同灌水频率(1 d 1次、2 d 1次、3 d 1次)、不同灌溉模式(纯清水灌溉、纯再生水灌溉、再生水-清水交替灌溉)条件下的土壤团聚体稳定性、体积质量、孔隙结构、土壤滴水穿透时间、灌水入渗时间和土壤水流运动非均匀程度的变化规律。【结果】非离子表面活性剂有利于提升土壤团聚体稳定性和土壤特征孔隙率、降低土壤体积质量,但也增大了土壤斥水性和水流运动的不确定性;低频率、高定额的灌水方式加剧了土壤团聚体的崩解,高频率、低定额的灌水方式增大了土壤水流运动的非均匀性;含非离子表面活性剂的灌溉水和清水交替灌溉模式具有提升土壤团聚体稳定性、增大土壤孔隙率,同时降低土壤斥水性和水流运动不确定性的优势。【结论】再生水农田灌溉宜采用再生水和清水交替灌溉模式,以平衡非离子表面活性剂对土壤的积极作用与潜在负面影响。
文摘Cationic Gemini surfactants, alkanediyl-α ,ω- bis(dimethyl dodecylammonium bromide) have been synthesized by the following method: firstly dodecyl bromide was prepared by the reaction of dodecanol with bromic acid in the presence of strong sulfuric acid. Dodecylbromide was then reacted with N,N- tetramethyl ethane diamine(or N,N- tetramethyl hexana diamine) to prepare the title- compounds. Micellization of these Gemini surfactants was investigated using conductivity measurement. The results showed that the critical micelle concentration(cmc) of the Gemini surfactants has a much lower value compared with that of the corresponding " monomer" . For a series of the Geminis with the same length(s) in the spacer chain, the cmc decreased with increasing the carbon number (m) in the alkyl chain. The aggregation number(N) of the micelle also drastically decreased with m. For the same value of m, the cmc varied slightly with s, which indicated that the electrostatic interaction between the ionic- groups of the " monomer" has been naturally changed duo to a link between the two ionic- groups of the " monomer" through a spacer. However, N was strongly decreased with s,which may be a reason of steric inhibition coming from the ionic- groups due to a link of spacer. With increasing temperature, micellization of the Gemini surfactants was slightly enhanced.
