Work

Transformation of Chrome Leather Waste into Nanofunctional Composite for the Remediation of Tannery Dye Wastewater

Year: 2025

Type: article

Abstract: High Resolution Image Download MS PowerPoint Slide The leather industry faces inevitable challenges in producing large volumes of chrome-containing solid waste as well as dye-containing colored wastewater. In this study, chrome-tanned leather shaving (CTLS), one of the major hazardous tannery solid wastes, was upcycled into a chromic oxide nanoparticles composite (Cr 2 O 3 @CTLS) through a thermochemical process and utilized to treat toxic tannery dye wastewater. The material exhibited a high fixed carbon content (69.56 ± 0.03%), indicating efficient carbonization. Fourier transform infrared (FTIR) analysis revealed several functional groups in Cr 2 O 3 @CTLS, while TGA showed minimal weight loss up to 450 °C (12%), reflecting the good thermal stability of the nanocomposite. Scanning electron microscopy (SEM) imaging revealed a highly mesoporous structure, attributed to the effective activation of KOH. The Brunauer–Emmett–Teller (BET) surface area and mean pore size of the composite are 57.98 m 2 g –1 and 4.83 nm (mesopore), respectively, thereby enhancing its capacity to adsorb complex dye molecules. The dye removal process (acid yellow dye-17) was optimized using response surface methodology with a central composite design (RSM-CCD) using the latest version of software. The optimal conditions for achieving 98% dye removal were determined within a contact time of only 120 min, using 2 g L –1 of adsorbent. Furthermore, the pseudo-second-order kinetics ( R 2 = 0.998) and the Temkin isotherm ( R 2 = 0.990) models provide the best mathematical descriptions, with a maximum adsorption capacity ( q max ) of 386.26 ± 16.04 mg g –1 derived from the Langmuir isotherm. The thermodynamic analysis revealed (Δ G < 0, Δ H > 0, and Δ S > 0) that the uptake process was feasible, exothermic, and spontaneous. The dye sorption mechanism was explored using X-ray photoelectron spectroscopy (XPS), SEM, energy-dispersive X-ray spectroscopy (EDS), FTIR, etc. and suggests that pore filling, diffusion, and hydrophobic and electrostatic interactions are involved in sorption. Moreover, Cr 2 O 3 @CTLS exhibited impressive reusability, maintaining a removal efficiency of 65.76% at the sixth cycle of dye adsorption, showcasing its economic viability in dye wastewater treatment. After six consecutive cycles, the material exhibited excellent structural stability, as evidenced by the similarity of X-ray diffraction (XRD) patterns between the pre- and postadsorbed Cr 2 O 3 @CTLS. The nonexistence of Cr (VI) in both solid and liquid phases was confirmed by XPS and ultraviolet–visible (UV–vis) analyses, respectively, ensuring its safe use in real-world water treatment.

Source: ACS Omega

DOI: 10.1021/acsomega.5c05477

Authors: Afrin Rahman Akhi, Amal Kanti Deb, Masud Hassan, Santosh Kumar Paul

Institutions: University of Dhaka, Guizhou University, University of Newcastle Australia

Language: English

Topic: Adsorption and biosorption for pollutant removal

Subfield: Water Science and Technology

Field: Environmental Science

Domain: Physical Sciences

SDGs: Responsible consumption and production, Clean water and sanitation

Open Access status: gold

Estimated APC paid: $1,935