Enhanced removal of methylene blue dye from its aqueous solutions using humic acid-functionalized alumina nanoparticles

Harvesting of cyanobacteria and phosphorus by electrocoagulation-flocculation-flotation: Role of phosphorus precipitation in cell separations and organics destabilization

A high level of phosphate triggers the excretion of algogenic organic matter (AOM) during algae blooming, leading to disinfection by-products (DBPs) formation. The presence of phosphate could impact cyanobacteria harvesting and AOM separations by electrocoagulation. This study aims to investigate the role of phosphate in cell separations and AOM destabilization by Al-based electrocoagulation-flocculation-flotation (EFF) for harvesting of cyanobacteria and phosphate. The Al-based EFF was conducted to harvest Microcystis aeruginosa (MA) with varied phosphate (0-10 mg/L) at 5 mA/cm2 and pH 8. Fluorescent organic fractions, molecular weight distributions, the properties of flocs and DBPs formation potential were fully investigated. The results showed that the EFF at a low level of phosphate (1 mg/L) effectively improves the harvesting of MA cells, phosphate and the reduction in dissolved organic matter (DOC) up to 99.5 %, 95 % and 50 %, respectively. However, the presence of concentrated phosphate (10 mg/L) alleviates cell harvesting and worsens AOM separations due to ineffective floc formation induced by the fast formation of inactive AlPO4 precipitates along with limited Al(OH)3. At such a condition, it worsens DBPs precursors minimization owing to AOM release from MA cells. The increase in the current density during EFF can compensate for cell harvesting efficiency even though at concentrated phosphate, but it further induces AOM release. It is concluded that Al-based EFF demonstrates an efficient harvesting of cyanobacteria, phosphorus and AOM separations from algae-laden water under phosphate impact.

Green synthesis of alumina nanoparticle using Hibiscus rosa-sinensis leaf extract as a candidate for molybdenum-99 adsorbent

Al₂O₃ nanoparticle is effectively used as an adsorbent for the low specific activity of molybdenum-99 (⁹⁹Mo). The Al₂O₃ nanoparticle was synthesized by the green synthesis method using Hibiscus rosa-sinensis leaf extract (HRE). The Al₂O₃ nanoparticle synthesized using 10% of the HRE has a crystallite size of 4.9 nm, a surface area of 254.6 m²/g, a pore size of 9.1 nm, a pore volume of 0.58 cm³/g and has a Mo adsorption capacity of 43.4 ± 6.1 mg Mo/g.

Surface modification of acid-functionalized mesoporous gamma-alumina for non-fission 99Mo/99mTc generator

Mesoporous gamma-alumina (MGA) was synthesized for neutron-activated ⁹⁹Mo adsorbent. Acid functionalization of the MGA was carried out to enhance the Mo adsorption capacity and the ⁹⁹Mo breakthrough profile. The acid-treated MGA has a more positive particle charge, rougher surface, smaller particle and pore size, larger surface area, and wider pore distance. The acid-treated MGA has a Mo adsorption capacity of 82.8 ± 6.3 mg Mo/g and resulted in ^99mTc eluate with the ⁹⁹Mo breakthrough at the acceptable level.