Characterization of carboxymethyl cellulose-based active films incorporating non-modified and Ag or Cu-modified Cloisite 30B and montmorillonite nanoclays

Physico-mechanical and antibacterial properties of carboxymethyl cellulose (CMC)-based films incorporating Cloisite 30B (C30B) and montmorillonite (MMT) clay nanoparticles (NPs) modified with Ag and Cu ions were investigated. X-Ray diffraction patterns for modified clays with Ag and Cu ions showed that they were effectively located in the interlayer space of C30B and MMT clay NPs and increased their interlayer spacing. Scanning electron microscopy showed a smooth and homogeneous structure for a pure CMC film. Films containing MMT had coarser and more heterogeneous surface compared to C30B film, suggesting a better dispersion of modified C30B in the matrix of CMC. Mechanical analysis showed that films containing Ag- or Cu-modified C30B NPs exhibited higher tensile strength than that of MMT films. The ultraviolet spectroscopy showed that nanocomposite films containing Ag modified C30B had the highest UV absorption compared to other samples. Water vapor permeability of CMC films loaded by Ag- or Cu-modified C30B and MMT NPs significantly decreased compared to those of non-modified types and control. Microbial tests revealed that Ag-modified clay NPs had significantly higher antibacterial activity than Cu-modified types against E. coli and S. aureus bacteria. Films loaded with non-modified C30B NPs had the second most antibacterial effect followed by non-modified MMT NPs and control films

Modification of bio-hydroxyapatite generated from waste poultry bone with MgO for purifying methyl violet-laden liquids

In the present work, biological hydroxyapatite (Bio-HAp) was generated from waste poultry bone and modified with magnesium oxide (MgO) nanoparticles (Bio-HAp/MgO) and used in the adsorption process of methyl violet (MV). The Bio-HAp and Bio-HAp/MgO mesoporous composites were characterized using physicochemical techniques. Bio-HAp and Bio-HAp/MgO composites had crystalline and mesoporous structures. The specific surface area of Bio-HAp/MgO mesoporous composites (14.7 m2/g) was higher and lower than that of Bio-HAp (4.6 m2/g) and MgO (154.9 m2/g), respectively. The effect of pH (2–10), temperature (25–45 °C), contact time (10–50 min), initial MV concentration (5–25 mg/L), and Bio-HAp/MgO quantity (0.5–2.5 g/L) on the adsorption efficiency was optimized through response surface methodology-central composite design (RSM-CCD). Among four isotherm models, the Freundlich isotherm (R2 > 0.98) was better matched with the equilibrium data. Based on the isotherm parameters (E, n, and RL), the MV adsorption process using Bio-HAp particles and Bio-HAp/MgO mesoporous composites is physical and desirable. The pseudo-second-order (R2 > 0.97) was more potent than the other models for modeling kinetic data. According to the thermodynamic investigation, the MV adsorption was an exothermic and spontaneous process. The mesoporous composite had good reusability to remove MV dye from liquid media up to 5 steps. Bio-HAp particles and Bio-HAp/MgO mesoporous composites were tested for treatment, which significantly reduced the dye content of the real sample. © 2020, Springer-Verlag GmbH Germany, part of Springer Nature

Uptake of anionic and cationic dyes from water using natural clay and clay/starch/MnFe2O4 magnetic nanocomposite

The present research was designed to explore the adsorption of sunset yellow (SY) and Nile blue (NB) from water using clay and clay/starch/MnFe2O4 magnetic composite. The magnetic composite was synthesized by chemical precipitation and the physical-chemical characteristics of the adsorbents were evaluated. The specific magnetic saturation values for MnFe2O4 nanoparticles and clay/starch/MnFe2O4 were obtained 31.88emu/g and 10.33emu/g, respectively. In the batch mode experiments, the effect of operational factors was studied. The pseudo-second-order had a better correlation coefficient compared to the pseudo-first-order, Elovich, and intraparticle diffusion models. The Langmuir and Freundlich model fitted the equilibrium data for adsorption of both dyes (SY and NB) using clay and clay/starch/MnFe2O4, respectively. The maximum adsorption capacity for the adsorption of SY and NB dyes using clay was 67.82 mg/g and 72.25 mg/g, respectively and these values increased by about 15% after using the clay/starch/MnFe2O4 composite. The negative value of Gibbs free energy and enthalpy parameters proved that the SY and NB adsorption is spontaneous and exothermic. A sample of textile wastewater was properly treated using adsorbents. Finally, clay and clay/starch/MnFe2O4 magnetic composite can be used as viable adsorbents for dyes removal from water and industrial wastewater

Influence of chitosan and magnetic iron nanoparticles on chromium adsorption behavior of natural clay: Adaptive neuro-fuzzy inference modeling

In the current study, the influence of iron oxide nanoparticles and chitosan (CS) on the adsorption capacity of natural clay for chromium removal from aqueous media was explored. Clay-based adsorbents (clay, CS/Clay, Clay/Fe3O4, and CS/Clay/Fe3O4) were manufactured and their physicochemical properties were identified. The effects of operating factors on the adsorption efficiency were optimized. The results showed that the adsorption equilibrium data for the clay, CS/Clay, and Clay/Fe3O4 corresponds to the Langmuir model, while for the CS/Clay/Fe3O4 is consistent with the Freundlich model. The maximum adsorption capacity (qmax) of Cr(VI) using clay, CS/Clay, Clay/Fe3O4 and CS/Clay/Fe3O4 were 63.69 mg/g, 80.30 mg/g, 97.08 mg/g, and 117.64 mg/g, respectively. It was showed that the addition of chitosan and Fe3O4 magnetic nanoparticles to the clay increases its adsorption capacity. The values of ΔG° and ΔH° parameter for Cr adsorption using adsorbents were negative, indicating that the removal process is spontaneous and exothermic. The kinetic behavior obeyed the pseudo-second-order model. The chromium removal process using all the adsorbents had a two-step mechanism. The wastewater of a leather factory was effectively treated using clay based-adsorbents. Based on R2, MSE, SSE, and ARE values, good agreement was observed between the ANFIS model and experimental outcomes