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排序方式: 共有1107条查询结果,搜索用时 15 毫秒
41.
Lu Xiang Yunlong Zhu Shuai Gu Dongyang Chen Xian Fu Yindong Zhang Guipeng Yu Chunyue Pan Yuehua Hu 《Macromolecular rapid communications》2015,36(17):1566-1571
A hypercrosslinked conjugated microporous polymer (HCMP‐1) with a robustly efficient absorption and highly specific sensitivity to mercury ions (Hg2+) is synthesized in a one‐step Friedel–Crafts alkylation of cost‐effective 2,4,6‐trichloro‐1,3,5‐triazine and dibenzofuran in 1,2‐dichloroethane. HCMP‐1 has a moderate Brunauer–Emmett–Teller specific surface (432 m2 g−1), but it displays a high adsorption affinity (604 mg g−1) and excellent trace efficiency for Hg2+. The π–π* electronic transition among the aromatic heterocyclic rings endows HCMP‐1 a strong fluorescent property and the fluorescence is obviously weakened after Hg2+ uptake, which makes the hypercrosslinked conjugated microporous polymer a promising fluorescent probe for Hg2+ detection, owning a super‐high sensitivity (detection limit 5 × 10−8 mol L−1).
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In this study, the effect of photo-Fenton process on the treatment of petrochemical waste water treatment was investigated. The influence of process conditions were determined by factorial design. Optimization of the process conditions were performed by central composite design. Under, optimized conditions lab scale and solar assisted pilot scale of petrochemical waste water treatment was performed. Three factors namely initial pH, H2O2 concentration (mM) and Fe2+ concentration (mM) executed the essential role in petrochemical waste water treatment. Central composite design resulted in the prediction of optimized value as 6.5 initial pH, 15.65 mM of H2O2 concentration and 2.09 mM of Fe2+ concentration. Under these conditions, the reduction in chemical oxygen demand (COD) percentage reached about 68.67 ± 2.8% after 280 min in pilot scale of solar assisted photo Fenton process of petrochemical waste water treatment. Thus, experimental design combined with advanced Fenton process can become a feasible unconventional method for petrochemical waste water treatment. 相似文献
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In this study, optimum conditions for adsorption of heavy metals such as Cu2+, Cd2+ and Pb2+ onto a low-cost, magnetically modified-alkali conditioned anaerobically digested sludge (MADS) adsorbent were obtained. Response Surface Methodology (RSM) incorporating Central Composite Design (CCD) of experiments was applied to optimize four independent process variables. Statistical analysis was executed by ANOVA and the quadratic model developed had regression coefficients of 0.959, 0.957 and 0.95 for Cu2+, Cd2+ and Pb2+, respectively. The independent variables such as pH, time and initial concentration positively influenced adsorption capacity, qe, whereas the value of qe decreased with an increase in MADS dosage. Model validation experiments for optimization of adsorption process showed comparable results with predicted values. The adsorption capacity of MADS adsorbent at optimum conditions found through RSM analysis was 29.721 mg L?1, 28.551 mg L?1 and 28.601 mg L?1 for Cu2+, Cd2+ and Pb2+ respectively. 相似文献
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砷锑污染在全球领域广泛存在,与常规的铁氧化物相比,微生物铁氧化生成的含Fe(Ⅲ)矿物对水中砷/锑(As/Sb)具有更强的吸附能力,并因其高效、实用和环境友好而具有广阔的应用前景,但微生物铁还原也可能导致被吸附的As/Sb再次释放。本文综述了微生物铁氧化还原作用对As/Sb去除影响的研究进展,归纳了铁矿物“合成-溶解-转化”的微生物循环过程以及该循环伴随的水中As/Sb固定、溶解与转化机理,整合了微生物合成Fe(Ⅲ)矿物的矿物学性质、对As/Sb固定的热动力学规律和络合机制,总结了微生物合成Fe(Ⅲ)矿物对As/Sb去除的影响因素,基于该研究的现存问题展望了利用微生物铁氧化还原作用去除As/Sb的发展方向。 相似文献
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Removal of metal ions from water can not only alleviate the scaling problem of domestic and industrial water, but also solve the water safety problem caused by heavy metal ion pollution. Here, we fabricate a positively charged nanofiltration membrane via surfactant-assembly regulated interfacial polymerization(SARIP) of 2-methylpiperazine(MPIP) and trimesoyl chloride(TMC). Due to the existence of methyl substituent, MPIP has lower reactive activity than piperazine(PIP) but stronger affinity to hexane, resulting in a nanofiltration(NF) membrane with an opposite surface charge and a loose polyamide active layer. Interestingly, with the help of sodium dodecyl sulfate(SDS) assembly at the water/hexane, the reactivity between MPIP and TMC was obviously increased and caused in turn the formation of a positively charged polyamide active layer with a smaller pore size, as well as with a narrower pore size distribution. The resulting membrane shows a highly efficient removal of divalent cations from water, of which the rejections of MgCl2, CoCl2 and NiCl2 are higher than 98.8%, 98.0% and 98.0%, respectively, which are better than those of most of other positively charged NF membranes reported in literatures. 相似文献
47.
《Arabian Journal of Chemistry》2022,15(5):103754
Red mud wastes have been converted into mesoporous zeolite socony mobile-5 (ZSM-5) followed by deposited titanium dioxide (TiO2) nanoparticles to generate synergy adsorption-photodegradation for removal of dye removal in waste water. The amount of TiO2 loading was varied to achieve optimum photocatalytic activity while maintaining the mesoporosity and high surface area of ZSM-5. Sol-gel method facilitated the formation of anatase TiO2 on the ZSM-5. The fourier transform infrared spectra clarified the formation of Si–O–Ti at 957 cm?1 by the exchanging the hydrogen ion with titanium ion, which proved by decreasing the absorption band of Si–OH and Si–O interaction at 964 and 944 cm?1, respectively. Sol-gel method also preserved the mesopore diameter of ZSM-5 at 3.5 nm which allow the diffusion of methylene blue (MB) molecules into the pores. However, the surface area and the pore volume were slightly reduced with increasing the TiO2 loading. The adsorption performance of samples showed that the increasing in the TiO2 loading led to the decreasing in the adsorption capacity. All samples showed the suitability towards the pseudo second order kinetic. The Langmuir isotherm was suitable to describe the adsorption mechanism by monolayer adsorption. Mesoporosity of ZSM-5 accelerated the adsorption of dye via the increase of mass transfer in the pore channel which confirmed by the low intercept of intraparticle diffusion model at the first stage. The photocatalytic test showed that 10% TiO2 loading on the ZSM-5 exhibited the highest methylene blue removal followed by 5% and 20% TiO2 loading. Optimization on the amount of photocatalyst and the pH of solution indicated the reaction favoured 1 g L?1 of catalysts and at alkaline pH. 10% TiO2/ZSM-5 also exhibited high stability and reusability up to four reaction cycles. Photocatalytic performance of 10% TiO2/ZSM-5 was further investigated on photodegradation of malachite green and rhodamine B organic dyes, which showed the photocatalytic efficiency of 73 and 88%, respectively. Superoxide radical, hydroxyl radical, and photogenerated electron were identified as the main active species for MB photodegradation based on the reduction of degradation rate following the addition scavenger molecules. 相似文献
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Xiaonan Duan Dr. Stéphane C. Corgié Prof. Daniel J. Aneshansley Prof. Peng Wang Prof. Larry P. Walker Prof. Emmanuel P. Giannelis 《Chemphyschem》2014,15(5):974-980
We report a new family of hierarchical hybrid catalysts comprised of horseradish peroxidase (HRP)–magnetic nanoparticles for advanced oxidation processes and demonstrate their utility in the removal of phenol from water. The immobilized HRP catalyzes the oxidation of phenols in the presence of H2O2, producing free radicals. The phenoxy radicals react with each other in a non‐enzymatic process to form polymers, which can be removed by precipitation with salts or condensation. The hybrid peroxidase catalysts exhibit three times higher activity than free HRP and are able to remove three times more phenol from water compared to free HRP under similar conditions. In addition, the hybrid catalysts reduce substrate inhibition and limit inactivation from reaction products, which are common problems with free or conventionally immobilized enzymes. Reusability is improved when the HRP–magnetic nanoparticle hybrids are supported on micron‐scale magnetic particles, and can be retained with a specially designed magnetically driven reactor. The performance of the hybrid catalysts makes them attractive for several industrial and environmental applications and their development might pave the way for practical applications by eliminating most of the limitations that have prevented the use of free or conventionally immobilized enzymes. 相似文献