Mokpo National University

Nickel-metal hydride (Ni-MH) batteries contain cobalt, manganese, nickel, and rare earth elements.To meet the demand for these critical metals, it is essential to recover them from secondary resources.In this study, separation experiments were conducted to recover pure cobalt, manganese and nickel solutions from a synthetic sulfuric acid leachate of spent Ni-MH batteries.The synthetic solutions employed in this study contained Co(II), Fe(III), Mn(II), Ni(II), Zn(II), Ce(III), La(III), and Nd(III).First, Fe(III) was removed by precipitation as Fe(OH)₃ at room temperatureSecond, an ionic liquid prepared by reacting Aliquat 336 and Cyanex 272 was used to selectively extract Zn(II) and REEs(III) from the filtrate.Third, Co(II) and Mn(II) were simultaneously extracted using saponified Cyanex 272, leaving pure Ni(II) in the raffinate.Fourth, after stripping of Co(II) and Mn(II) from the loaded Cyanex 272, Mn(II) was selectively extracted over Co(II) with D2EHPA.The optimal conditions for each separation step were determined by analyzing the effects of various parameters.As a result, a process consisted of precipitation and solvent extraction was proposed to recover pure cobalt, manganese and nickel sulfate solutions from the synthetic sulfuric acid leachate of spent Ni-MH batteries.Moreover, all separation processes were carried out at room temperature, reducing energy consumption.

To prevent microbial contamination, antimicrobial preservatives need to be added in multi-dose biopharmaceuticals; however, it often introduces risks to protein stability, potentially compromising therapeutic efficacy. In this study, we investigated the effects of different preservatives (benzyl alcohol, m-cresol, phenoxyethanol, and benzalkonium chloride) on the biophysical stability of trastuzumab, a monoclonal antibody widely used for treatment of HER2 receptor-positive cancers. Among the preservatives tested, benzyl alcohol (1.0 % v/v) and m-cresol (0.3 % w/v) significantly reduced the monomeric content after 5 days of end-over-end agitation stress. Benzyl alcohol was associated with a surge in nano- to micro-sized particles (21-fold increase) and decreased thermal stability (ΔT_m: -5.39 °C). m-Cresol uniquely triggered visible particle formation (>100 µm) within 72 h, raising concerns for injectable biologics. Benzalkonium chloride (0.01 %-0.04 % w/v) exhibited inconsistent concentration-dependent behavior, initially showing increase in subvisible aggregates before stabilizing through micelle formation at higher concentrations, albeit with irreversible secondary structural shifts toward β-sheet motifs. Conversely, phenoxyethanol (0.5 % v/v) exhibited higher compatibility, preserved the monomeric content, and suppressed particle generation to baseline levels. These findings underscore the necessity of preservative-specific compatibility assessments in formulation design for therapeutic biologics, positioning phenoxyethanol as a promising candidate for trastuzumab preservation owing to the balance between its antimicrobial efficacy and minimal destabilization.