Chemical Engineering Publications

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Chemical Engineering Publications

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Browsing Chemical Engineering Publications by Author "Hildebrandt, D."

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    Modulated Synthesis of a Novel Nickel-Based Metal−Organic Framework Composite Material for the Adsorptive Desulfurization of Liquid Fuels
    (Industrial & Engineering Chemistry Research, 2021) Mguni, L.L.; Yao, Y.; Ren, J.; Liu, X.; Hildebrandt, D.
    Removing sulfur from liquid fuels has become an important issue in a global society. Modulated synthesis is known to improve the crystallinity of materials, ease of handling, control of crystallite size, and degree of aggregation. A group of adsorbents [activated carbon (AC), a novel synthesized Ni-based metal–organic framework (Ni-BDC), and composites of AC@Ni-BDC treated with different concentrations of nitric acid and modulator (formic acid)] were characterized using X-ray diffractometer (XRD), high-resolution transmission electron microscopy (HR-TEM), Fourier transform infrared spectroscopy (FTIR), Brunauer–Emmett–Teller (BET), and temperature-programmed desorption (TPD)-pyridine studies. The adsorbents were also evaluated for adsorptive desulfurization. The quantities of both AC and the modulator were observed to influence the nucleation of Ni-BDC, crystallite size, and crystallinity. The adsorption activity of the composite toward thiophene (TH) was the average of the two materials (i.e., AC and Ni-BDC), while the activity doubled toward dibenzothiophene (DBT) and 4,6-dimethyldibenzothiophene (4,6-DMDBT) with respect to the excepted average. The improved activity was attributed to enhanced pore structure, crystallinity, and synergistic effects that produced stronger acidic sites.
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    Processing Of Gold-Bearing Sand,Dumps: A Case Study In Zimbabwe
    (CISA, 2017-10) Hlabangana, N.; Bhondayi, C.; Mguni, N. G; Hildebrandt, D.; Danha, Gwiranai
    In this article, we investigate the possibility of reprocessing gold bearing gold dumps for gold as a sustainable way of reviving the mining sector in Zimbabwe. Heap or vat leaching is a process that has been extensively used for the recovery of valuable metals like copper, gold (Au) and silver. The ore is prepared for vat leaching by either crushing or milling it into fine and deslimed material. It is then placed into a container (vat), which has a partial filter floor. Cyanide solution can then be injected either through the filter section of the floor or added to the top of the ore charge.