Dye Adsorption by Leather Waste: Mechanism Diffusion, Nature Studies, and Thermodynamic Data

Abstract

Tannery solid waste (leather) is a possible adsorbent of dye contaminants in wastewater. In this paper the nature and mechanisms of dyes adsorption by chromium-tanned leather waste (CTLW) are proposed and discussed on the basis of isotherms, adsorption kinetics, and thermodynamics of three dyes: Red 357, Black 210, and Yellow 194 in aqueous solutions. Langmuir, Brunauer–Emmett–Teller (BET) and Henry isotherm models were used to fit the adsorption equilibrium data, respectively. The kinetic data were evaluated using boundary layer mass transfer and intraparticle diffusion models. The boundary layer mass transfer coefficient was in the order of 10–6 and 10–5 m·min–1 for the three studied dyes. However, the intraparticle diffusion were of the order of 10–8 and 10–11 m2·min–1 for the Red 357 and Black 210 dyes, respectively, demonstrating that intraparticle diffusion is the predominant mass transfer mechanism of these dyes. The values of ΔH, ΔS, ΔG, and E a suggest that adsorption is spontaneous, exothermic, and chemical in nature. The chemical nature is also confirmed by Fourier transform infrared (FT-IR) analysis.

Adsorption of methylene blue and eosin yellow using porous carbon prepared from tea waste: Adsorption equilibrium, kinetics and thermodynamics study

“…The 10 discharge of industrial wastewater containing different dye 11 contaminants causes serious environmental problems. A variety 12 of methods such as adsorption, coagulation and flocculation, 13 oxidation, chemical precipitation, and so forth, have been reported 14 for waste water treatment [1][2][3][4][5][6][7]. Among these, adsorption is well 15 established and superior technique because of their low cost, the 16 simplicity of design and availability of adsorbents.…”

CHAPTER 16. Chromium in Tannery Wastewater

“…95 New effluent treatment techniques, such as adsorption of dyes from leather dyeing, have been shown to be successful. 68 As for the effluents from the tanning stage, the recycling of these is still not practiced comprehensively in the industry and there are uncertainties about the actual necessary dosage of chemical reagents responsible for the precipitation of chromium. The precipitation for chromium removal from tanning wastewater enables the reuse of the metal when it is redissolved to be used again in the process.…”

“…[66][67][68] Adsorption is a transfer process of one or more constituents (adsorbates) of a fluid phase (adsorptive) to the surface of a solid phase (adsorbent). In the adsorption process, molecules present in the fluid phase are attracted to the interfacial zone due to the existence of uncompensated attractive forces at the surface of the adsorbent.…”

“…69 Recent studies have shown good results for adsorption of tannery effluent trivalent chromium 70 and removal of dyes from leather dyeing. 68 Researchers have studied adsorbents using more economical materials for chromium removal from water, such as cellulose adsorbents, 71 beet pulp, 72 polyacrylonitrile fibers, 73 coal developed from residual materials, 74,75 biosorbents, 76,77 ash residue 78 and zeolites. 79 The biggest advantages of the adsorption process for effluent treatments are in its low initial investment, simplicity of design and operation, nontoxicity, lower energy use and superior efficiency relative to both conventional and other non-conventional processes.…”

Mass transfer models for the adsorption of Acid Red 357 and Acid Black 210 by tannery solid wastes

“…Based on the high values of R 2 presented in Table 2, it can be seen that the Langmuir (equation (8)) and BET models (equation (9)) were able to explain the equilibrium adsorption of Acid Red 357 and Acid Black 210, respectively. Table 2 shows also the thermodynamic parameters, which were estimated by the Van't Hoff's plot (Piccin et al, 2013). The negative DG values indicated that the dyes adsorption onto TSW was a spontaneous and favorable process.…”