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.

Sonophotocatalytic degradation of malachite green in aqueous solution using six competitive metal oxides as a benchmark.

A comparison study examines six different metal oxides (CuO, ZnO, Fe3O4, Co3O4, NiO, and α-MnO2) for the degradation of malachite green dye using four distinct processes. These processes are as follows: sonocatalysis (US/metal oxide), sonocatalysis under ultra-violet irradiation (US/metal oxide/UV), sonocatalysis in the presence of hydrogen peroxide (US/metal oxide/H2O2), and a combination of all these processes (US/metal oxide/UV/H2O2). The effective operating parameters, such as the dosage of metal oxide nanoparticles (MONPs), the type of the process, and the metal oxides' efficiency order, were studied. At the same reaction conditions, the sonophotocatalytic is the best process for all six MOsNPs, CuO was the better metal oxide than other MOsNPs, and at the sonocatalysis process, ZnO was the best metal oxide in other processes. It was found that the metal oxide order for sonocatalytic process is CuO > α-MnO2 ≥ ZnO > NiO ≥ Fe3O4 ≥ Co3O4 within 15-45 min. The order of (US/metal oxide/UV) process is ZnO ≥ NiO ≥ α-MnO2 > Fe3O4 ≥ CuO ≥ Co3O4 within 5-40 min. The order of (US/ MOsNPs/ H2O2) process is ZnO ≥ CuO ≥ α-MnO2 ≥ NiO > Co3O4 > Fe3O4 within 5-20 min. The maximum removal efficiency order of the sonophotocatalytic process is ZnO ≥ CuO > α-MnO2 > NiO > Fe3O4 ≥ Co3O4 within 2-8 min. The four processes degradation efficiency was in the order US/MOsNPs ˂ US/MOsNPs/UV ˂ US/MOsNPs/H2O2 ˂ (UV/Ultrasonic/MOsNPs/H2O2). Complete degradation of MG was obtained at 0.05 g/L MONPs and 1 mM of H2O2 using 296 W/L ultrasonic power and 15 W ultra-violet lamp (UV-C) within a reaction time of 8 min according to the MOsNPs type at the same sonophotocatalytic/H2O2 reaction conditions. The US/metal oxide/UV/H2O2 process is inexpensive, highly reusable, and efficient for degrading dyes in colored wastewater.

Homogeneous and heterogeneous catalytic oxidation of some azo dyes using copper(II) ions.

The kinetics of the homogeneous and heterogeneous catalytic oxidation processes of three azo dyes in presence of copper (II) - ions, copper (II) - ions - supported on alumina and on zinc oxide as well as copper ammonia complex supported on alumina were investigated in aqueous solutions. The dyes are Chromotrope 2B (C2B), Chromotrope 2R (C2R) and Chrysophenen (CRY). The reaction progress was followed by monitoring the decrease in absorbance at ℷmax 512, 511 and 401 nm, respectively. The rate of reaction increased with increasing either the concentration of the dye or the catalyst, giving a plateau at high concentrations of the catalyst. On the other hand, the rate of reaction increased gradually with increasing hydrogen peroxide concentration attaining a maximum then decreased thereafter. The reaction rate was also increased with increasing pH and temperature and was found to be entropy controlled. This work could be applied for dye baths water reuse to reduce costs in textile and dyeing factories as will as for environmental purposes.

Effect of simultaneous proprioceptive-visual feedback on gait of children with spastic diplegic cerebral palsy.

OBJECTIVE: To evaluate the effect of simultaneous proprioceptive - visual training on gait parameters in children with spastic diplegic cerebral palsy. METHOD: Gait parameters of 30 spastic diplegic children (age range 4-6 years) were evaluated before and after treatment by Tekscan's Walkway Pressure system. They were randomly and equally assigned into two groups (study and control). All children received regular therapeutic exercise program for one hour. In control group walked for 30 minutes without feedback, while those in study group walked for 30 minutes with proprioceptive-visual feedback. Duration of treatment was 3 times/week for 8 successive weeks. RESULTS: There were significant differences after treatment in spatial parameters and temporal parameters of both groups with more improvement in study group than control one, and insignificant difference in kinetic gait parameters. CONCLUSION: The simultaneous proprioceptive - visual training might improve spatial and temporal gait parameters with no effect on kinetic gait parameters of children with spastic diplegic cerebral palsy.

Fluorescence quenching N,N-bis(2,6-dimethylphenyl)-3,4:9,10-perylenetetracarboxylic diimide (BDPD) laser dye by colloidal silver nanoparticles.

The fluorescence quenching N,N-bis(2,6-dimethylphenyl)-3,4:9,10-perylenetetra-carboxylic diimide (BDPD) by colloidal silver nanoparticles (AgNPs) was studied in methanol and ethylene glycol by steady state fluorescence measurements. The Stern-Volmer quenching rate constant (Ksv) was calculated as 8.1 × 10(8) and 8.22 × 10(8) M(-1) in methanol and ethylene glycol respectively. Taking the fluorescence lifetime of BDPD in the absence of silver nanoparticles as 3.2 ns, the values of the fluorescence quenching rate constants (kq = Ksv/τ) are calculated as 2.54 × 10(17) and 2.56 × 10(17) M(-1) s(-1) in methanol and ethylene glycol respectively. From the data, fluorescence resonance energy transfer and / or electron transfer processes play a major role in the fluorescence quenching of BDPD by AgNPs in methanol and low concentrations of Ag NPs in ethylene glycol. The static quenching rate constant in ethylene glycol was calculated by modified Stern-Volmer equation as V = 8.86 × 10(9) M(-1). For dynamic quenching, the radius of quenching sphere volume r values were found to be 68.3 and 70.6 nm in ethanol and ethylene glycol, respectively. For static quenching in ethylene glycol the effective radius of quenching sphere action (kinetic radius) was calculated as r = 152 nm.

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.

Structural and photophysical properties of (2E)-3-[4-(dimethylamino) phenyl]-1-(naphthalen-1-yl) prop-2-en-1-one (DPNP) in different media.

The spectral and photophysical properties of a new chalcone derivative (2E)-3-[4-(dimethylamino) phenyl]-1-(naphthalen-1-yl) prop-2-en-1-one (DPNP) containing donor-acceptor group has been synthesized and characterized on the basis of the spectral (IR, (1)HNMR & (13)C NMR) and X- ray crystallographic data. The effect of solvents on photophysical parameters such as singlet absorption, molar absorptivity, oscillator strength, dipole moment, fluorescence spectra, and fluorescence quantum yield of DPNP have been investigated comprehensively. Significant red shift was observed in the emission spectrum of DPNP compared to the absorption spectrum upon increasing the solvent polarity, indicating a higher dipole moment in the excited state than in the ground state. The difference between the excited and ground state dipole moments (Δµ) were obtained from Lippert-Mataga and Reichardts correlations by means of solvatochromic shift method. The effects of medium acidity on the electronic absorption and emission spectra of DPNP were studied. The interaction of DPNP with colloidal silver nanoparticles (AgNPs) was also studied in ethanol and ethylene glycol using steady state fluorescence quenching measurements. The fluorescence quenching data reveal that dynamic quenching and energy transfer play a major role in the fluorescence quenching of DPNP by Ag NPs.