Reversible adsorption of metalworking fluids (MWFs) on Cu-BTC metal organic framework

Metalworking fluids(MWFs) are classified as hazardous substances. Due to the characteristics of the stable oil–water emulsions, it requires more costly and complicate treatment techniques to remove oil from spent MWFs. Metal organic frameworks(MOFs) are a porous network material used to remove contaminants from environment. One of the most prominent of MOFs is HKUST-1 or Cu-BTC. In this study, the Cu-BTCs were prepared by solvothermal method in various conditions and used as absorbent for removing oil micelles in MWF emulsion. The particle size of all synthesized Cu-BTCs ranged from ≈80 to 400 nm. The ability of all synthesized Cu-BTCs to remove oil micelle was greater than 95% in 60 min, while the capacity of GAC was obtained the result for only 6.8%. The maximum adsorption capacity(q _(max)) of oil micelles on Cu-BTCs was 1666.7 mg·g^(-1). The highest removal capacity of oil micelles in MWF emulsion is greater than 99% in 24 h by using Cu-BTCs washed with either butanol or ethanol.

Photocatalytic degradation of paraquat using nano-sized Cu-TiO_2 /SBA-15 under UV and visible light

Photocatalytic degradation of paraquat using mesoporous-assembled Cu-TiO2 /SBA15 under UV and visible light was investigated.The catalyst was synthesized by impregnation of Cu-TiO2 colloids onto SBA-15.The colloids of Cu-TiO2 were prepared via solgel method while the mesoporous support was prepared using hydrothermal technique.The catalyst was characterized using X-ray diffraction,nitrogen adsorption-desorption,transmission electron microscopy,UV diffuse reflectance spectroscopy,Zeta potential and X-ray adsorption spectroscopy.Results from characterizations showed that Cu doped TiO2 had a small crystalline size and was welldispersed on SBA-15.The inclusion of SBA-15 significantly enhanced the photocatalytic activity of the catalyst.Among the three types of undoped catalyst in this study （P25,TiO2,TiO_2 /SBA-15）,TiO2 /SBA-15 yielded the highest degradation of paraquat for all pH under UV illumination.Meanwhile 2 wt.% Cu-TiO2 /SBA-15 yielded the highest activity under visible light.

Enhancement of elemental mercury adsorption by silver supported material

Mercury, generally found in natural gas, is extremely hazardous. Although average mercury levels are relatively low, they are further reduced to comply with future mercury regulations,which are stringent in order to avoid releasing to the environment. Herein, vapor mercury adsorption was therefore investigated using two kinds of supports, granular activated carbon（GAC） and titanium dioxide（Ti O2）. Both supports were impregnated by silver（5 and 15 wt.%）,before testing against a commercial adsorbent（sulfur-impregnated activated carbon, SAC）. The adsorption isotherm, kinetics, and its thermodynamics of mercury adsorption were reported.The results revealed that Langmuir isotherm provided a better fit to the experimental data.Pseudo second-order was applicable to describe adsorption kinetics. The higher uniform Ag dispersion was a key factor for the higher mercury uptake. Ti O2 supported silver adsorbent showed higher mercury adsorption than the commercial one by approximately 2 times.Chemisorption of mercury onto silver active sites was confirmed by an amalgam formation found in the spent adsorbents.

Biochar and pyrolytic gas properties from pyrolysis of simulated municipal solid waste(SMSW)under pyrolytic gas atmosphere

Municipal Solid Waste(MSW)was converted into high-grade solid fuels(biochar)and gaseous product via thermal pyrolysis under pyrolytic gas atmosphere.The experiment was carried out in a packed-bed reactor at the temperature range of 600-800℃ in both atmospheres of N_(2) and pyrolytic gas.Gas,liquid,and solid products were analyzed by gas chromatograph and elemental analysis.Amount of biochar obtained from both atmospheres were not significantly different.CH_(4) and CO_(2) in pyrolytic gas promoted the release of volatile in the MSW,resulting in lower ratio of VM/FC,ca.0.13.The atomic ratios of O/C and H/C were around 0.02-0.11 and 0.005-0.035,respectively.These values were equivalent to anthracite coal type.On the other hand,the liquid fuel yield under pyrolytic gas condition was found to be higher,compared with that under N_(2) condition.In addition,the enhancement of H_(2) and CO production was accompanied by the decrease in CH_(4) and CO_(2) output.Overall,the operating condition at 800℃ or higher with reaction times longer than 4 min were recommended for production of biochar with fuel qualities approaching anthracite coal.