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The synthesis and growth behavior of the chemically modified ostrich bone wastes as bioadsorbents for the removal of methyl orange from aqueous solutions have been investigated. The ostrich bone wastes were treated with cetyltrimethylammonium bromide (CTABr) and sodium dodecyl benzene sulfonate (SDBS). The synthesized biomaterials were characterized by several physicochemical techniques. The modified ostrich bone with CTABr was found to be effective as adsorbent for the removal of methyl orange (MO) from aqueous solutions. The effect of the experimental conditions on the adsorption behavior was studied by varying the contact time, initial MO concentration, temperature, initial pH, chemical modification process, and amount of adsorbent. The contact time to attain equilibrium for maximum adsorption (90%) was found to be 50 min. The adsorption kinetics of MO has been studied in terms of pseudo-first- and -second-order kinetics, and the Freundlich, Langmuir and Langmuir-Freundlich isotherm models have also been applied to the equilibrium adsorption data. The adsorption process was spontaneous and endothermic in nature and followed pseudo-second-order kinetic model., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Heterogeneous Mn nanoparticles (5-30 nm diameter) is found to be a nanomaterial for the rapid removal of large quantities of toxic dye (methyl orange) from aqueous solution, with wide ranging potential applications. The synthesized materials were characterized with different methods such as FT-IR spectroscopy, CHN elemental analysis, BET, SEM, TEM, ICP-OES and EPR. The contact time to obtain equilibrium for maximum adsorption of methyl orange was 20 min. EPR of Mn ions evidenced that most of the covalently bond active sites of the nano-adsorbent are in the form of Mn(III) ions at the surface. The heterogeneous Mn(III)-Cl ions were found to be effective adsorbent for the removal of methyl orange from solution. The adsorption of methyl orange ions has been studied in terms of pseudo-first-order and pseudo-second-order kinetics, and the Freundlich, Langmuir and Langmuir-Freundlich isotherm models have also been applied to the equilibrium adsorption data. The adsorption process was spontaneous and endothermic in nature and followed pseudo-second-order kinetic model., (Copyright © 2014 Elsevier Inc. All rights reserved.)

This article describes the preparation of a nanoadsorbent containing Co-nanoparticles decorated functionalized SiO2-Al2O3 mixed-oxides as a scavenger toward removal of methyl orange. SiO2-Al2O3 mixed-oxides were functionalized with pyridine-2-carbaldehyde and thereafter, in the next step, Co-nanoparticle was prepared over the modified mixed-oxides. The as-prepared nanoadsorbent was characterized by Fourier transform infrared (FTIR), UV-visible diffuse reflectance spectra (UV-vis DRS), inductively coupled plasma atomic emission spectroscopy (ICP-AES), Brunauer-Emmett-Teller (BET), transmission electron microscopy (TEM), electron paramagnetic resonance (EPR), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Results showed that Co-nanoparticle with average size of about 5-25 nm was immobilized successfully on the surface of modified mixed-oxides and was widely dispersed. EPR and CV of Si/Al-PAEA=PyCA@CoNP confirmed that most of the covalently bond active sites of the nano-adsorbent are in the form of Co(II) ions. The supported cobalt is a suitable and efficient adsorbent for the removal of methyl orange from aqueous solution. The heterogeneous Co-NPs were found to be effective adsorbent for the removal of methyl orange ions from solution. The adsorption process was spontaneous and endothermic in nature and followed pseudo-second-order kinetic model. The CV and EIS of the Co-NPs-MO indicates an easily oxidizable environment, this being in agreement with the FTIR data, where the electron density at Co-NPs is higher due to the presence of a donor-electron ligand (methyl orange), that is, reduction of Co-NPs from +3 to +2 oxidation state is more favored., (Copyright © 2014 Elsevier Inc. All rights reserved.)