Solid waste sub-driven acidic mesoporous activated carbon structures for efficient uranium capture through the treatment of industrial phosphoric acid

This research study presents bio-char manufacturing from a solid waste (rice-straw) by low-temperature pyrolysis as a new trend. The as-produced char (named as BC) and its sub-driven hydrochloric and nitric acids activated carbons (labeled as HAC, and NAC respectively) were employed as adsorbents for uranium removal from a commercial grade of phosphoric acid. Morphological and structural characteristics of the presented carbonaceous structures were accomplished utilizing Fourier Transform Infrared (FTIR) Spectroscopy and Transmission Electron Microscopy (TEM). The uranium adsorption process via these three structures was then performed via the batch technique at various operating conditions. It was observed that the labeled structure as HAC has an increased adsorption capacity, compared to the other two adsorbents. Thus, it could attain a higher level of uranium species removal than both NAC and BC. Hence, HAC could be subsequently concluded as the structure of most suitability, among the three adsorbents, for uranium taking out from industrial phosphoric acid. The collected adsorption results by the three structures had been next examined by diverse kinetic and isotherm models. By all structures in this study, the presented adsorption processes were found to follow the pseudo-second-order model and perfectly match the Langmuir isotherm model. The applied three sorbents' sorption capacity was 2.3, 2.5, and 3.3 for BC, NAC, and HAC, respectively. This confirms that the bio-char activation with hydrochloric acid has the most positive impact on bio-char's sorption characteristics The various thermodynamics factors (Delta H, Delta G and Delta S) could reveal that these processes are exothermic exploits. (C) 2021 Published by Elsevier B.V.

Automated summary

This study presents the manufacturing of bio-char from rice-straw by low-temperature pyrolysis as a new trend, and the use of activated carbons for uranium removal from phosphoric acid. Among the three structures studied, it was found that hydrochloric acid activated carbon (HAC) has the highest adsorption capacity for uranium removal. The adsorption processes of the three structures followed the pseudo-second-order model and Langmuir isotherm model, with the sorption capacity of 2.3, 2.5, and 3.3 for BC, NAC, and HAC, respectively.