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Mesoporous silicas were synthesized via a surfactant-templated sol-gel route using castor oil as the templating agent under acidic medium. The resulting silicas were subsequently amine functionalized with 3-aminopropyltriethoxysilane (NH2-MTS), [3-(2-aminoethylamino)-propyl]trimethoxysilane (NN-MTS), and [3-(diethylamino)propyl]trimethoxysilane(DN-MTS) to introduce surface basicity. Surface physicochemical properties were characterized by field emission gun scanning electron microscopy (FEGSEM), nitrogen porosimetry, X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), X-ray diffraction (XRD), and diffuse reflectance infrared fourier transform spectroscopy (DRIFTS). As-synthesised materials exhibit type IV adsorption-desorption isotherms characteristic of mesoporous structures. Clusters of spherical shaped materials were observed by FEGSEM, suggesting growth of silica occurs within colloidal dispersions. High-resolution N 1s XP spectra and DRIFT spectra confirmed the presence of amine groups in the organo-amine functionalised mesoporous silicas. The amine functionalised mesoporous silicas were active for the transesterification of tributyrin with methanol, with conversion found to increase from NH2-MTS< NN-MTS< DN-MTS.

Background Approximately 69% of population in Tanzania lacks better sanitation, while 45.6% lacks access to clean and safe water. To leverage this shortage, several technologies have been used for purifying water from various sources; however, there is still persistence of waterborne diseases. Main body This article reviewed the efficiency of common water filters in removing water contaminants such as Escherichia coli, fluoride, TSS, turbidity, nitrate, virus, BOD, COD, fecal coliform and color. Common water filters available in Tanzania markets include slow sand filter, ceramic filter, bone char, membrane purifier and bio sand filter. The effectiveness of each technology was evaluated in terms of its ability to remove water contaminants. Ceramic filter was found to be less expensive technology compared to the rest. Ineffectiveness of common water filters can be linked to persistence of waterborne diseases in Tanzania. Conclusion Ability of water filters in viral removal is of greater concern. This study suggests a ceramic filter as the best filter among all common filters available in Tanzania. Ceramic filters can be synthesized by locally available materials such as clay, saw dust, rice husk ashes and flour which make it efficient in removing all water contaminants, especially viruses.

A series of sulfated zirconia (SZ) were synthesized and evaluated for catalytic esterification of ricinoleic acid obtained from the castor oil with butanol at 110 °C. The effect of alcohols’ chain length was studied using butanol (C4), propanol (C3), ethanol (C2) and methanol (C1) at 65 °C, and reflux of corresponding alcohol boiling points. The synthesized catalysts were characterized using nitrogen porosimetry, X-ray powder diffraction, thermogravimetric analysis and Diffuse Reflectance Infrared Fourier Transform Spectroscopy. Analysis of ricinoleic conversion was performed using gas chromatography. Sulfuric acid loading improved the surface area of zirconia at a lower dose. The surface areas of the catalysts increased as the concentrations of sulfuric acid solution were increased from 0.025 to 0.10 M, after which the decline was observed. SZ obtained at 0.05 M H2SO4 (0.05SZ) gave the optimal catalytic activity compared to the other series of SZ used. The ricinoleic acid conversion decreased with increase of alcohol alkyl chain from C1-C4 at 65 °C, but increased under the reflux temperature of the corresponding alcohols, with the maximum conversion being 47% at 118 °C for the reaction involving butanol. Overall, the synthesized SZ catalysts are deployable in biodiesel production from castor oil upon optimizing other conditions. Keywords: Ricinoleic acid; Sulfated zirconia; Biodiesel production