Copper supported Dowex50WX8 resin utilized for the elimination of ammonia and its sustainable application for the degradation of dyes in wastewater.

To obtain high efficient elimination of ammonia (NH4+) from wastewater, Cu(II), Ni(II), and Co(II)) were loaded on Dowex-50WX8 resin (D-H) and studied their removal efficiency towards NH4+ from aqueous solutions. The adsorption capacity of Cu(II)-loaded on D-H (D-Cu2+) towards NH4+ (qe = 95.58 mg/g) was the highest one compared with that of D-Ni2+ (qe = 57.29 mg/g) and D-Co2+ (qe = 43.43 mg/g). Detailed studies focused on the removal of NH4+ utilizing D-Cu2+ were accomplished under various experimental conditions. The pseudo-second-order kinetic model fitted well the adsorption data of NH4+ on D-Cu2+. The non-linear Langmuir model was the best model for the adsorption process, producing a maximum equilibrium adsorption capacity (qmax = 280.9 mg/g) at pH = 8.4, and 303 K in less than 20 min. The adsorption of NH4+ onto D-Cu2+ was an exothermic and spontaneous process. In a sustainable step, the resulting D-Cu(II)-ammine composite from the NH4+ adsorption process displayed excellent catalytic activity for the degradation of aniline blue (AB) and methyl violet 2B (MV 2B) dyes utilizing H2O2 as an eco-friendly oxidant.

Nano-silica from white silica sand functionalized with PANI-SDS (SiO2/PANI-SDS) as an adsorbent for the elimination of methylene blue from aqueous media.

Natural resources including sand are one of the best approaches for treating dye-polluted wastewater. The SiO2/PANI-SDS nanocomposite was synthesized by self-assembly and intermolecular interaction. The physicochemical features of the SiO2/PANI-SDS nanocomposite were explored by FT-IR, XRD, SEM, TEM, EDX, and N2 adsorption-desorption techniques to be evaluated as an adsorbent for the MB. The surface area of the SiO2/PANI-SDS is 23.317 m2/g, the pore size is 0.036 cm3/g, and the pore radius is 1.91 nm. Batch kinetic studies at different initial adsorbate, adsorbent and NaCl concentrations, and temperatures showed excellent pseudo-second-order. Several isotherm models were applied to evaluate the MB adsorption on the SiO2/PANI-SDS nanocomposite. According to R2 values the isotherm models were fitted in the following order: Langmuir > Dubinin-Radushkevich (D-R) > Freundlich. The adsorption/desorption process showed good reusability of the SiO2/PANI-SDS nanocomposite.

Selective removal of ammonia from wastewater using Cu(II)-loaded Amberlite IR-120 resin and its catalytic application for removal of dyes.

Cationic ligand exchange is one of the most predominant mechanisms for the removal of ammonia from wastewater through complex formation. The complexation technique occurs between the metal ions loaded on the surface of Amberlite IR-120 and ammonia which is present in the medium. Cu(II)-loaded Amberlite IR-120 (R-Cu2+) was prepared and described using FT-IR, TGA, SEM, and EDX techniques. The prepared R-Cu2+ was applied for the elimination of ammonia from an aqueous solution. Different cations such as Co2+ and Ni2+ were loaded onto Amberlite IR-120 to study the impact of counter cation on the removal efficiency of ammonia. The ammonia removal percentage followed the order; R-Cu2+ > R-Ni2+ > R-Co2+. The effects of contact time, pH, initial concentration, temperature, and coexisting ions on the removal of ammonia from wastewater by R-Cu2+ were investigated. The equilibrium adsorbed amount of ammonia was found to be 200 mg/g at pH = 8.6 and 303 K within 60 min using 0.1 g R-Cu2+ and an initial concentration of ammonia of 1060 mg/L. The removal of ammonia using R-Cu2+ obeyed the non-linear plot of both Freundlich and Langmuir isotherms. According to the thermodynamic parameters, the adsorption of ammonia onto R-Cu2+ was an endothermic and spontaneous process. The time-adsorption data followed the pseudo-second-order and intraparticle diffusion models. Moreover, the resulting product (R-Cu(II)-amine composite) from the adsorption process exhibited high catalytic activity and could be low-cost material for the elimination of dyes such as aniline blue (AB), methyl green (MG), and methyl violet 2B (MV2B) from wastewater.

Eco-Friendly NiO/Polydopamine Nanocomposite for Efficient Removal of Dyes from Wastewater.

The rapid development of industries discharges huge amounts of wastewater that contain surface water. For this reason, we used NiO/polydopamine (NiO/PDA) nanocomposite as an efficient material for the removal of Methyl violet 2B from water. It was synthesized and then characterized by Fourier Transform Infrared (FT-IR) spectroscopy, X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Energy Dispersive X-ray (EDX) analysis, Transmission Electron Microscopy (TEM), and Brunauer-Emmett-Teller (BET). The EDX analysis confirmed the presence of O, Ni, N, and C. The composite has an average particle size of 18 nm. Its surface area is 110.591 m2/g. It was found that the efficiency of dye removal by adsorption on NiO/PDA exceeded that of bare NiO. The adsorption capacity of NiO and NiO/PDA are 126 and 284 mg/g, respectively. The effects of adsorbent dose, dye concentration, and pH on the removal efficiency were examined. The efficiency increased with increasing the adsorbent dose and pH, but dropped from 85 to 73% within 30 min as the initial dye concentration was increased from 0.984 to 4.92 mg/L. Such a drop in the removal efficiency is due to the blocking of the surface-active sites of NiO/PDA, with the high population of dye molecules derived from the continuous increase in dye concentration. The adsorption results of the dye fitted well with the pseudo-second-order kinetics and Langmuir isotherm. The reusability data showed that NiO/PDA was stable across three adsorption-regeneration cycles, thus it can be considered a good recyclable and efficient adsorbent. Because of these results, it can be considered that this method can be applied for the treatment of wastewater.

Application of montmorillonite-Cu(II)ethylenediamine catalyst for the decolorization of Chromotrope 2R with H2O2 in aqueous solution.

The kinetics of decolorization of Chromotrope 2R (C2R) was studied spectrophotometrically using the montmorilloniteK10-Cu(II)ethylenediamine composite (MMTK10-Cu(en)2) as catalyst and H2O2 as oxidant in aqueous solution. The catalyst was prepared and characterized by SEM, FTIR, XRD and TGA techniques. The dependence of reaction rate on H2O2 concentration was examined under UV irradiation in the presence and absence of the catalyst, and in the presence of the catalyst without the UV irradiation. In all these reaction systems, the rate increased up to a maximum value and then decreased. The rate increased with increasing the concentration of the dye reaching a maximum. Also, the rate of decolorization reaction showed a significant increase with increasing the amount of the catalyst and temperature. The addition of NaCl to the reaction medium has accelerated the rate effectively. A similar catalyst, MMTKSF-Cu(en)2, has also been employed and was found to be less efficient compared with MMTK10-Cu(en)2.