Abstract:Heavy metals such as Cu(II) are widespread in the environment, and the impact of heavy metals on the environment of soils depends on the ability of soils to immobilize these pollutants. It is necessary to investigate the mechanism of interaction between heavy metal and soil from a soil remediation perspective. In this study, a series of experiments were conducted to investigate the adsorption and desorption behavior of Cu(II) in silty clay. Several impact factors such as pH, organic matter, temperature, and co… Show more
“…The sorption of metal complex dyes onto pine sawdust particles was also successfully interpreted by the Elovich equation ( Özacar and Şengil, 2005 ). The applicability of the Elovich model in the case of SG dye adsorption by GWTW suggests it is a heterogeneous diffusion process ( Xie et al., 2018 ). Figure 5 Kinetic experimental data and modeling for the adsorption of SG dye by GWTW.…”
Groundwater treatment waste (GWTW), as an environmentally friendly renewable nanomaterial, was implemented for the removal of anodized aluminum dye Sanodure Green (SG) from aqueous solutions. The capability of the SG metal complex dye removal was assessed by measuring solution decoloration and chromium elimination degree. GWTW was characterized using FTIR, SEM, EDX, TEM, XPS and surface area measurements. Kinetic curves were obtained by changing initial dye concentration, pH, temperature and adsorbent dose. Kinetic studies showed that up to 90 % of SG dye was removed within a contact time of 20 min. The adsorption of the dye was favourable at 293 K temperature in the acidic pH region (pH 1.5–2.0) with maximum adsorption capacity 185 mg g
−1
. Langmuir-Freundlich isotherm model as well as hyperbolic tangent, diffusion-chemisorption and Elovich kinetic models accurately describe the dye removal process. The calculated thermodynamic parameters confirmed that SG dye removal occurred spontaneously and exothermically. The magnitude of enthalpy change (ΔH
°
= −35.80 kJ mol
−1
) was in agreement with the electrostatic interaction. The adsorption potential of GWTW for SG dye removal was also evaluated using a real wastewater produced after dyeing of anodized aluminum.
“…The sorption of metal complex dyes onto pine sawdust particles was also successfully interpreted by the Elovich equation ( Özacar and Şengil, 2005 ). The applicability of the Elovich model in the case of SG dye adsorption by GWTW suggests it is a heterogeneous diffusion process ( Xie et al., 2018 ). Figure 5 Kinetic experimental data and modeling for the adsorption of SG dye by GWTW.…”
Groundwater treatment waste (GWTW), as an environmentally friendly renewable nanomaterial, was implemented for the removal of anodized aluminum dye Sanodure Green (SG) from aqueous solutions. The capability of the SG metal complex dye removal was assessed by measuring solution decoloration and chromium elimination degree. GWTW was characterized using FTIR, SEM, EDX, TEM, XPS and surface area measurements. Kinetic curves were obtained by changing initial dye concentration, pH, temperature and adsorbent dose. Kinetic studies showed that up to 90 % of SG dye was removed within a contact time of 20 min. The adsorption of the dye was favourable at 293 K temperature in the acidic pH region (pH 1.5–2.0) with maximum adsorption capacity 185 mg g
−1
. Langmuir-Freundlich isotherm model as well as hyperbolic tangent, diffusion-chemisorption and Elovich kinetic models accurately describe the dye removal process. The calculated thermodynamic parameters confirmed that SG dye removal occurred spontaneously and exothermically. The magnitude of enthalpy change (ΔH
°
= −35.80 kJ mol
−1
) was in agreement with the electrostatic interaction. The adsorption potential of GWTW for SG dye removal was also evaluated using a real wastewater produced after dyeing of anodized aluminum.
“…Studies have shown that Elovich model is more suitable for the adsorption kinetics of sediments or soils where there are large changes in activation energy (Nitish et al 2017). According to the model, the results showed that the adsorption kinetics of Cu(II) was a heterogeneous diffusion process during which the activation energy changed significantly (Gunasundari 2017;Xie et al 2018). The adsorption of Cu(II) was positively correlated with the τ, i.e.…”
Section: Resultsmentioning
confidence: 99%
“…The adsorption isotherm is used to describe the relationship between adsorption capacity and concentration of the adsorbate in solution after reaching equilibrium on the solid phase (Xie et al 2018;Yan et al 2018;Botello-Gonzalez et al 2019). Here, the Langmuir, Freundlich, Temkin and Dubinin Radushkevic models were used to evaluate the adsorption isotherm process of Cu(II) by the lake sediments under different hydrodynamic conditions.…”
Discharges from industrial and agricultural processes into water bodies can result in the accumulation of heavy metals such as Cu(II) in the sediment via various physical and chemical interactions. While there are many studies of the adsorption of heavy metals by sediment, few have considered the effects of hydrodynamic conditions. Here, the adsorption of Cu(II) by sediments under different hydrodynamic conditions was studied using a particle entrainment simulator. The sediment samples were obtained from the Poyang Lake basin in China. Models describing pseudo-first-order, pseudo-second-order, Elovich and intraparticle diffusion kinetics and the Langmuir, Freundlich, Temkin and Dubin Radushkevich adsorption isotherms were used to evaluate the adsorption of Cu(II) by the sediments under different hydrodynamic conditions. The results showed that adsorption equilibrium for Cu(II) by the sediment was attained within 4 hours and increased with increasing shear stress; the kinetics were consistent with pseudo-second-order and Elovich models, indicating that chemical processes were involved in adsorption; the adsorption isotherms could be described by the Langmuir and Freundlich models. Changes in the sediment shear stress had little effect on the maximum adsorption capacity and values ranged from 0.9425 to 1.0634 mg/g. The results indicated that the adsorption sites for Cu(II) in soil were heterogeneous.
“…4, and Freundlich eq. 5) [24] were tested in the fitting of the degradation data of Sandocryl dye by Ca-ALG/Ag nanocomposite beads titanium [25] [26]. , , are the Langmuir, Freundlich, and Timken, adsorption equilibrium constants, respectively; and are the equilibrium concentration, and the adsorption capacity, respectively.…”
Silver nanoparticles (Ag NPs) are widely used as engineered nanomaterials in many advanced nanotechnologies, due to their versatile, easy and cheap preparations combined with peculiar chemical-physical properties. Their increased production and integration in environmental applications including water treatment raise concerns for their impact on humans and the environment. In this study, gamma radiation dose of 20 kGy was utilized to induce the synthesis silver nanoparticles (Ag NPs) in the alginate micro beads to prepare calcium Alginate/Ag (Ca-ALG/Ag) nanocomposite beads. These beads were then used to degrade toxic basic dyes in waste water. Initially, Ca-ALG /Ag nanocomposite beads were synthesized and characterized using Ultra Violet-visible spectrum (UV-Vis), Scanning Electron Microscope (SEM), X-Ray Diffraction (XRD) and Transmission Electron Microscope (TEM) for confirming the formation of Ag NPs and morphological study. The catalytic efficiency of the resulting Ca-ALG/Ag nanocomposite beads is evaluated for the degradation of dyes such sandocryl blue dye in the presence of NaBH4. The catalytic degradation of sandocryl blue dye was very fast in the present conditions: 0.1 g of catalyst 5 ml NaBH4 and the optimum time for complete reduction was 30 min. The pseudo-first order, pseudo second order and intra particle diffusion model used to evaluate the kinetic models and the mechanism of the degradation. Results showed that the degradation kinetics best fit the pseudo-second-order model and Langmuir isotherm model. The Biopolymer-based nanocomposite beads of calcium alginate, and Ag NPs can be applied to reduce dyestuff, where it is economically viable and environmentally friendly.
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