Ceramic hydroxyapatite foam as a new material for Bisphenol A removal from contaminated water

Statistical physics modeling study of an environmentally friendly and efficient adsorbent derived from the brown macroalgae Bifurcaria bifurcata for the removal of Bisphenol A

The brown macroalgae Bifurcaria bifurcata was valued and used to develop a carbonaceous material activated by H2SO4 (AC-BB@H2SO4), with the goal of assessing its adsorption ability against Bisphenol A (BPA). During the adsorption experiments, the effects of the adsorbent dose, solution pH, and contact time were examined, and the results were m = 0.4 g/L, pH = 8.3, and t = 120 min, with an elimination yield of 91.6 %. With comparatively high R2 values, the pseudo-second-order kinetic model perfectly fitted the experimental data. Langmuir's model was found to be the best appropriate for describing the adsorption equilibrium of BPA on AC-BB@H2SO4. The thermodynamic findings show that BPA adsorption on AC-BB@H2SO4 was spontaneous, favorable, and endothermic in nature. Even after six cycles of reuse, regeneration testing demonstrated that our adsorbent could eliminate BPA by >50 %. The BPA adsorption mechanism's statistical physics control parameters were determined and analyzed. BPA's adsorption energies were <40 kJ/mol, indicating that the interactions between BPA and AC-BB@H2SO4 were governed by physical forces (i.e., hydrogen bonding and van der Waals and electrostatic interactions). All of these intriguing findings indicate that our carbonaceous material might have direct ramifications in the field of wastewater treatment, notably for the clearance of BPA, which is difficult to biodegrade.

Reducing the negative impact of ceftriaxone and doxycycline in aqueous solutions using ferrihydrite/plant-based composites: mechanism pathway

The adsorption of ceftriaxone (CET) and doxycycline (DOX) from aqueous solution using ferrihydrite/plant-based composites (silica rice husk) to reduce their negative impact on the ecosystem was adequately studied. On the other hand, phosphate and humic acid are often found in water and soil; in view of this, their effects on the adsorption of CET and DOX were investigated. The results showed that the removal of ceftriaxone decreased with an increase in pH, while that of doxycycline did not. Ferrihydrite with 10% silica rice husk (Fh-10%SRH) has the highest maximum adsorption capacity of 139 and 178 mg g^-1 for CET and DOX, respectively, at room temperature based on Liu's adsorption isotherm. This implies that the presence of silica rice husk increases CET and DOX uptake due to an increase in the pore volume of FH-10%SRH. The results showed that phosphate had a significant inhibition role on CET adsorption and minor on DOX, whereas humic acid salt affected neither case. Increase in temperature up to 333 K favored the adsorption of both contaminants. The proposed adsorption mechanisms of ceftriaxone are electrostatic interaction, n-π interaction, and hydrogen bond, while that of DOX entails n-π interaction and hydrogen bond.

Zinc-doped hydroxyapatite: an UVA light photocatalyst for the removal of bisphenol A

Zinc-doped hydroxyapatite obtained by a simple co-precipitation method achieved a photocatalytic removal > 80% of Bisphenol A.