Ball milling potassium ferrate activated biochar for efficient chromium and tetracycline decontamination: Insights into activation and adsorption mechanisms

Temperature dependent fabrication of various rod and rhombohedral-shaped mesoporous Co3O4 crystals and their capability towards elimination of toxic Cr(vi) ions from the aquatic environment

“…via oxidation/reduction processes. 125 Herein, a large number of free electrons are produced from the oxygen vacancies present in the Co 3 O 4 lattice 81,109,126 and they can eventually reduce the chemisorbed Cr( vi ) ions into Cr( iii ). The acid–base equilibrium equation is presented in eqn (12) and the redox reactions in both acidic and basic media are presented in eqn (13) and (14), respectively:The existence of both Cr( iii ) and Cr( vi ) peaks in the post-catalytic XPS study completely supports the above predicted mechanistic pathway (see Section 3.3.7.3.).…”

“…The presence of minor Cr(VI) after catalytic cycles may be due to the use of excess Cr(VI) as the starting material and impurities formed during the washing stage. [108][109][110] All the XPS atomic concentration data for pre-and post-catalytic Co 3 O 4 (400 1C) are recapitulated in Table 8. 3.3.8.…”

Preparation of hydrochar by one‐step hydrothermal carbonization with potassium ferrate‐assisted activation for the removal of tetracycline in water

“…The average particle size of hydrochar decreased from 22 μm (HTCC) to 7 μm (HTC2Fe), indicating that K 2 FeO 4 could catalyze the reaction and increase the dissociation of the raw material. At a magnification of 10 k, the surface of the modified hydrochar was found to become more porous with an increase in the amount catalyst and more surface‐loaded substances, and this could increase the specific surface area of the hydrochar and enhance its physical adsorption performance 35 …”

“…At a magnification of 10 k, the surface of the modified hydrochar was found to become more porous with an increase in the amount catalyst and more surface-loaded substances, and this could increase the specific surface area of the hydrochar and enhance its physical adsorption performance. 35 The nanoscale particles enriched on the surface of the modified hydrochar may be carbon-encapsulated iron-core nanospheres. The hydrolysis of saccharide and wood-chip molecules has been shown to be promoted by iron ions catalyzed at 180 °C.…”

Highly efficient removal of methylene blue from aqueous solution by magnetic biochar prepared from hawthorn seeds

“…Chemical activation has some advantages over physical activation such as lower processing temperatures and shorter processing times. 23 In addition, the carbon yield in physical activation is usually lower than in chemical activation. Besides, both the starting material and activation time might affect the structural properties of biochar and have a strong influence on its porous structure.…”