Engineering Research Center for Waste Oil Recovery Technology and Equipment, Ministry of Education, Chongqing Technology and Business University , Chongqing 400067, China.
College of Materials Science and Engineering, Chongqing University , Chongqing 400044, China.
Environ Sci Technol. 2017 Sep 19;51(18):10519-10525. doi: 10.1021/acs.est.7b02901. Epub 2017 Sep 8.
Here we report a facile and cost-effective wet-chemical approach to the synthesis of calcium sulfate hemihydrate nanowires (HH NWs, CaSO·0.5HO), and their robust performance in immobilizing water molecules to the crystal lattice of CaSO and then separating them from a surfactant-stabilized water-in-oil emulsion (mean droplet size of around 1.2 μm). Every gram of HH NWs are capable of treating 20 mL emulsion (water content: 10.00 mg mL) with a separation efficiency of 99.23% at room temperature, and this efficiency can be further improved by tuning the surface charge density of HH. Along with the water immobilization, HH NWs are converted to large cubic-like calcium sulfate dihydrate microparticles (DH, CaSO·2HO, mean size: 50 μm), and the accompanied size increment enables efficient collection of the solid phase from oil. DH microparticles can be regenerated into HH NWs, which retain the high performance of the original NWs. Such a unique renewable feature improves the economics of our method and simultaneously prevents the secondary pollution. Further economic evaluation finds that purification of every cubic meters of emulsion (water content: 10.00 mg mL) will cost about $34.18 for HH NWs, much lower than the $490.78 for the previously reported HH NPs, and $11 052.05-$23 420.32 FeO NP-based adsorbents, respectively. With the high efficiency, easy collection, low cost, and renewable feature, HH NWs show highly promising applications in the field of oil purification and recycle.
在这里，我们报告了一种简便且经济高效的湿化学方法，用于合成半水硫酸钙纳米线（HH NWs，CaSO·0.5H2O），并研究了其在将水分子固定到 CaSO 晶格中以及将其从表面活性剂稳定的油包水乳液（平均液滴尺寸约为 1.2μm）中分离出来的强大性能。每克 HH NWs 能够处理 20mL 乳液（含水量：10.00mg/mL），在室温下的分离效率为 99.23%，通过调节 HH 的表面电荷密度可以进一步提高效率。随着水的固定，HH NWs 转化为大的立方状二水硫酸钙微颗粒（DH，CaSO·2H2O，平均尺寸：50μm），伴随的尺寸增加使固体相从油中高效收集。DH 微颗粒可以再生为 HH NWs，保持了原始 NWs 的高性能。这种独特的可再生特性提高了我们方法的经济性，同时防止了二次污染。进一步的经济评估发现，对于每立方米含水量为 10.00mg/mL 的乳液（含水量：10.00mg/mL），使用 HH NWs 进行净化的成本约为 34.18 美元，远低于之前报道的 HH NPs 的 490.78 美元，以及分别为 11052.05 美元-23420.32 美元的基于 FeO NPs 的吸附剂。HH NWs 具有高效率、易于收集、低成本和可再生的特点，在油水净化和回收领域具有广阔的应用前景。
