Chemicals and fuels from wastes and CO₂ : a route of sustainability

2026-05-08T06:36:02Z

Chemicals and fuels from wastes and CO₂ : a route of sustainability Yao, Yali The conversion of waste CO2 into sustainable fuels and chemicals through advanced technologies like Fischer-Tropsch synthesis, highlighting its environmental benefits and potential applications.

Construction industry 4.0 for inclusive smart city development

2025-02-15T20:35:46Z

Construction industry 4.0 for inclusive smart city development Thwala, Research Professor Wellington Didibhuku

Decoding quality from a single cell to organisational optimisation

2025-03-13T10:15:56Z

Decoding quality from a single cell to organisational optimisation Ramdass, Kemlall

Optimization of Cr (VI) removal from aqueous solution with activated carbon derived from Eichhornia crassipes under response surface methodology

2023-06-13T09:49:44Z

Optimization of Cr (VI) removal from aqueous solution with activated carbon derived from Eichhornia crassipes under response surface methodology Fito, Jemal; Tibebu, Solomon; Nkambule, Thabo T. I. Abstract Tannery industries’ effluent contains a high concentration of Cr (VI) which has the potential to affect the environment and public health. Therefore, this study aimed to investigate the optimization of Cr (VI) adsorption by activated carbon (AC) derived from Eichhornia crassipes from an aqueous solution. The adsorbent was activated with dilute sulfuric acid followed by thermal activation. AC was characterized using proximate analysis, SEM, FTIR, X-ray diffraction, and the BET method. The Cr (VI) removal optimization process was performed using a central composite design under the response surface methodology. The proximate analysis showed that the moisture content, volatile matter, ash content, and fixed carbon of the activated carbon were 5.6%, 18.2%, 14.4%, and 61.8% respectively. The surface areas of the Eichhornia crassipes before activation, after activation, and after adsorption were 60.6 g/m2, 794.2 g/m2, and 412.6 g/m2 respectively. A highly porous structure with heterogeneous and irregular shapes was observed in the SEM micrograph. In the FTIR analysis, different peaks are indicated with various functional groups. The intensity of XRD peaks decreased as 2 theta values increased, which indicates the presence of an amorphous carbon arrangement. The point of zero charge (pHpzc) of the activated carbon was found to be 5.20. A maximum Cr (VI) removal of 98.4% was achieved at pH 5, contact time 90 min, adsorbent dose 2 g, and initial Cr (VI) concentration of 2.25 mg/L. Statistically significant interactions (P < 0.05) were observed between the initial Cr (VI) concentration and adsorbent dose as well as the initial Cr (VI) concentration and contact time. Langmuir adsorption isotherm fitted the experimental data best, with an R2 value of 0.99. The separation constant (RL) indicates that the adsorption process is favorable. The kinetic experimental data were best fitted with the pseudo-second-order model with an R2 value of 0.99 whereas the adsorption rate is controlled by intraparticle and extragranular diffusion processes. Generally, the AC has the potential to be a strong adsorbent candidate for wastewater treatment at the industrial level.

Research Outputs (Civil and Chemical Engineering)

Chemicals and fuels from wastes and CO₂ : a route of sustainability

Construction industry 4.0 for inclusive smart city development

Decoding quality from a single cell to organisational optimisation

Optimization of Cr (VI) removal from aqueous solution with activated carbon derived from Eichhornia crassipes under response surface methodology