Simple synthesis and characterization of l-Cystine functionalized δ-FeOOH for highly efficient Hg(II) removal from contamined water and mining waste

• Published in: Chemosphere (Oxford) Vol. 215; pp. 422 - 431
• Main Authors: Maia, Luiz F.O., Hott, Rodrigo C., Ladeira, Patricia C.C., Batista, Bruno Lemos, Andrade, Thaina G., Santos, Mayra S., Faria, Márcia C.S., Oliveira, Luiz C.A., Monteiro, Douglas S., Pereira, Márcio C., Rodrigues, Jairo Lisboa
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.01.2019
• Subjects: Adsorption; Brazil; Cysteine; Cystine - chemistry; FeOOH; Ferric Compounds - chemistry; Filters; Hydrogen-Ion Concentration; Kinetics; Mercury; Mercury - analysis; Mercury - isolation & purification; Rivers - chemistry; Water Pollutants, Chemical - analysis; Water Pollutants, Chemical - isolation & purification; Water Purification - methods; FeOOH; Cysteine; Filters; Adsorption; Mercury
• ISSN: 0045-6535; 1879-1298
• DOI: 10.1016/j.chemosphere.2018.10.072

l-Cystine functionalized δ-FeOOH nanoparticles (Cys-δ-FeOOH) were prepared by a cheap and straightforward method for using as an adsorbent of Hg(II) in aqueous solution. X-ray diffraction (XRD), attenuated total reflectance infrared spectroscopy (ATR-IR), and Raman spectroscopy confirmed that Cys-δ-FeOOH was successfully synthesized. Cys-δ-FeOOH with 14 nm crystal size, 34 m2 g−1 surface area, and 9 nm pore size were produced. The functionalization of the δ-FeOOH surface with cysteine decreases the point of zero charge of the iron oxyhydroxide from 8.4 in δ-FeOOH to 5.7 in Cys-δ-FeOOH, which is beneficial for the adsorption of Hg(II) near neutral pH. The maximum Hg(II) adsorption capacity of the δ-FeOOH and Cys-δ-FeOOH at pH 7 were found to be 35 mg g−1 and 217 mg g−1, respectively. The kinetics data were best fitted by a pseudo-second-order model, suggesting chemical adsorption on the surface and pores of Cys-δ-FeOOH nanoparticles. Finally, δ-FeOOH and Cys-δ-FeOOH filters were constructed for purifying mercury-contaminated water. The filters were highly efficient to treat mercury-contaminated water from a Brazilian river, reducing the concentration of mercury in water to values below the allowed limits by the current legislation. [Display omitted] •A novel δ-FeOOH functionalized l-cysteine adsorbent has been synthesized by simple method.•The Cys-δ-FeOOH shows high adsorption capacity for Hg(II) removal from contaminated water.•The adsorbent showed excellent reutilization performance and good anti-interference ability.•Filter of Cys-δ-FeOOH was highly efficient treat contaminated wastewater from a Brazilian river.