A series of mesoporous NiO catalysts with high specific surface area were prepared by a simple hydrothermal method and modified by cetyltrimethylammonium bromide (CTAB) as the crystal structure directing regent. The characterization with SEM, XRD, BET, and H2-TPR results demonstrated that the introduction of CTAB effectively improved the dispersion, specific surface area, and pore volume and redox ability of NiO, and thus exposed more active sites. Meanwhile, the NiO catalyst with a CTAB/NiSO4·6H2O molar ratio of 2/3 exhibited the better catalytic ozonation performance of toluene, formaldehyde, methanol, and ethyl acetate than NiO. The in-situ DRIFTS elucidated the reaction path of catalytic ozonation of toluene and indicated that the introduction of CTAB facilitated the complete oxidation of by-products into CO2and H2O.Keywords:catalytic ozonation;typical VOCs;NiO catalyst;CTAB modification
Zeyu Zhang,Haotian Tan,Yongliang Zhao,Qin Wang,Haitao Wang
Hypothesis Conventional strategies based on emulsion templates to produce porous materials are complicated and not environmental-friendly, thus inspiring a facile and novel approach via polymerization of aqueous foams. Graphene oxide (GO) has been proved as a very efficient Pickering stabilizer for oil-in-water or water-in-oil emulsions, however, it has rarely (if any) been used to stabilize aqueous foams. It is of high interest to prepare GO-stabilized aqueous foams and subsequent porous hydrogels after polymerization of the aqueous phase. Experiments GO was slightly hydrophobized with cetyltrimethylammonium bromide (CTAB) and then used to stabilize aqueous foams containing a water-soluble monomer , N-(3-Sulfopropyl)-N-methacroyloxyethyl-N,N-dimethylammonium betaine (SBMA). After polymerizing the aqueous phase, macroporous zwitterionic hydrogels (PSBMA) were prepared. The pore morphology of macroporous PSBMA were observed by a field-emission scanning electron microscope . Findings The wettability of modified GO by both water and air, indeed has a significant influence on the air bubble size and size distribution as well as the pore size of resulting macroporous PSBMA hydrogels. The pore size and pore interconnectivity of the hydrogels can be tailored by simply varying the surface property and concentration of GO in water. PSBMA hydrogels exhibit a pronounced uptake of aqueous NaCl solutions and efficient separation of oil-in-water emulsions.
With the aim of gathering uranium from ground aquatic environment in which uranium mainly occurs in negative species, the montmorillonite (MT) intercalated with cetyltrimethylammonium bromide (CTAB) was fabricated. X-ray diffraction and Fourier transform infrared spectroscopy were utilized to prove the entrance of CTAB into MT. Adsorption of uranium onto CTAB-MT was studied with respect to effect of pH, carbonate, calcium, humic acid, contact time, initial uranium concentration, and temperature. The adsorption negatively depended on pH, carbonate and calcium ion and humic acid concentrations. CTAB-MT had a higher uranium adsorption ability. The maximum monolayer uranium adsorption amount of CTAB-MT calculated by well fitted Langmuir model was determined as 213.31 mg g −1 , preceding 82.17 mg g −1 of MT. The adsorption kinetics was well fitted by pseudo-second-order model. The uptake mechanism involved ion exchange and electrostatic attraction. The adsorption was endothermic and spontaneous. The results demonstrated CTAB-MT was promising to separate uranium from ground water.
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