Synthesis of sucrose-derived porous carbon-doped ZrxLa1-xOOH materials and their superior performance for the simultaneous immobilization of arsenite and fluoride from binary systems

- A superior PSC-Zr0.79La0.21OOH composite was prepared for AsO33− and F− removal.
- Prepared PSC-Zr0.79La0.21OOH was dependent of pH for both F− and AsO33− adsorption.
- PSC-Zr0.79La0.21OOH selectively adsorbs AsO33− in a triple component system.
- Mechanism of both F− and AsO33− adsorption was explained based on HSAB concept.
- Maximum adsorption capacities were achieved for AsO33− and F− by PSC-Zr0.79La0.21OOH.

Amorphous forms of mixed lanthanum-zirconium oxyhydroxide (ZrxLa1-xOOH) composite materials, containing porous sucrose carbon as a dopant (PSC-ZrxLa1-xOOH), were successfully prepared via co-precipitation and characterized by BET surface area analysis, Fourier transform infrared spectroscopy (FTIR), powder X-ray diffraction (PXRD), scanning electron microscopy (SEM) Energy-dispersive X-ray spectroscopy (EDX) and thermogravimetric analysis (TGA). These synthesized materials were utilized for the simultaneous adsorption of AsO33− and F− from a binary mixture solution in batch tests. The ZrxLa1-xOOH and PSC-ZrxLa1-xOOH composite materials showed both fast adsorption rates and high adsorption capacities towards AsO33− and F− in aqueous solution. Most attractively, ZrxLa1-xOOH and PSC-ZrxLa1-xOOH showed better F− adsorption capacity when the pH was lower than 7, better AsO33− removal when the pH was higher than 9 and were superior to previously reported metallic oxide-based sorbents. The mechanism can be interpreted based on the HSAB principle, where the bimetallic oxyhydroxides become “soft acids”, while La3+ and Zr4+ are categorized as “hard acids”. Moreover, the PSC-ZrxLa1-xOOH adsorbent demonstrated high selectivity for AsO33− in the co-existence of other ions in a triple component system. The fast adsorption kinetics and high capacity make the designed PSC-ZrxLa1-xOOH adsorbent a promising advanced material for the removal of AsO33− and F− from water in practical applications.

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