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首页> 外文期刊>Separation and Purification Technology >Absorption of dissolved organic species from water using organically modified silica that swells
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Absorption of dissolved organic species from water using organically modified silica that swells

机译：使用溶胀的有机改性二氧化硅从水中吸收溶解的有机物

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Organically modified silica that rapidly and reversibly swells to >3 times their dry volume have been recently described. Here, these organosilica materials were demonstrated to have the ability absorb trichloroethyiene (TCE), perchloroethylene (PCE), methyl t-butyl ether (MTBE), toluene, naphthalene, acetone, 1,4-dioxane, and 1-butanol from water. Direct experimental comparisons indicated that swellable organically modified silica (SOMS) has in many instances greater capacity than activated carbon and molecular sieves and possesses the ability to capture a wide range of dissolved polar and non-polar organic contaminants. The absorption of organic species to SOMS is enhanced by matrix expansion leading to non-selective capture of organics beyond what could only be attributed to physisorption. This process appears to be facilitated by initial adsorption events unlatching the collapsed matrix leading to the opening of nanometer-scale pores within the tensioned SOMS material, thus providing volume for absorption. Partition coefficients for the absorption of organic species from water by SOMS ranged from 2.8 x 10~5 to 1.0 x 10~2, and vary depending on polarity of the contaminant, concentration, and the total mass of contaminant absorbed. Maximum capacity exceed three times the dry weight of the absorbent under conditions of high contaminant concentration. SOMS was repeatedly regenerated with mild thermal treatment (60-110°C) in air to evaporate absorbates from the matrix which could be subsequently collected. Only a slight decrease in effectiveness is observed after regeneration. Absorption is equally effective from salt water. Minimal loss of capacity and affinity is lost when extracting environmentally relevant concentrations of TCE from a topsoil/water mixture, presumably due to a molecular sieving effect.
机译：近来已经描述了有机改性的二氧化硅，其迅速且可逆地膨胀至干体积的> 3倍。在此，这些有机硅材料被证明具有从水中吸收三氯乙炔（TCE），四氯乙烯（PCE），甲基叔丁基醚（MTBE），甲苯，萘，丙酮，1,4-二恶烷和1-丁醇的能力。直接的实验比较表明，可溶胀的有机改性二氧化硅（SOMS）在许多情况下具有比活性炭和分子筛更大的容量，并具有捕获各种溶解的极性和非极性有机污染物的能力。有机物对SOMS的吸收通过基质扩展而增强，从而导致有机物的非选择性捕获超出了只能归因于物理吸附的范围。最初的吸附事件会释放塌陷的基质，从而导致在张紧的SOMS材料内形成纳米级孔隙，从而为吸收提供了空间，从而促进了这一过程。 SOMS从水中吸收有机物的分配系数介于2.8 x 10〜5到1.0 x 10〜2之间，并且取决于污染物的极性，浓度和吸收的污染物的总量。在高污染物浓度的条件下，最大容量超过吸收剂干重的三倍。 SOMS在空气中经过温和的热处理（60-110°C）反复再生，以蒸发掉基质中的吸收物，随后可以收集这些吸收物。再生后仅观察到效力略有下降。从盐水吸收同样有效。当从表土/水混合物中提取与环境相关浓度的三氯乙烯时，损失的容量和亲和力损失最小，这可能是由于分子筛分作用所致。

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