Application of novel butane-1,4-dioic acid-functionalized cellulosic biosorbent for aqueous cobalt ion sequestration

The study involved the synthesis of a novel adsorbent via the direct carbonylation of butane-1,4-dioic acid impregnated Alhagi root powder to its acid anhydride analogue and the subsequent esterification of the highly cellulosic plant material by the anhydride to an ester of high carboxyl content. The high carboxyl content of the synthesized adsorbent was recorded as 451.76 m.eq -COOH/100 g sample. The adsorbent was effectively characterized using Scanning electron microscopy, Energy dispersion X-ray, and Fourier-transform infrared spectroscopy, as well as utilized for aqueous cobalt ion sequestration. Similarly, the effect of the process variable on the carboxyl content and adsorption capacity of 'ATAG' was elucidated. The Dubinin-Radushkevich model satisfactorily predicted the isotherm data. Meanwhile, the intraparticle diffusion model was best at predicting the kinetic data at adsorbate concentration of 300 and 450 mg/L, while the pseudo-first-order model emerged as the best fit at 600 mg/L concentration. The maximum adsorption capacity of 188.67 mg/g was recorded at optimum adsorption conditions (pH 6.0, 60 min, and 30 degrees C), and the adsorption mechanism was also proposed. The abundant surface oxygenous functional groups on 'ATAG' positively influenced its adsorption capacity; thus, making it a promising biosorbent for aqueous Co (II) uptake.

Automated summary

The study successfully synthesized a novel adsorbent with high carboxyl content and investigated its adsorption performance towards aqueous cobalt ions. By utilizing various characterization techniques and models, the adsorption mechanism and optimum adsorption conditions of the adsorbent under different process variables were revealed.