Mostafa R. Abukhadra

Photocatalytic removal of Congo red dye using MCM-48/Ni2O3 composite synthesized based on silica gel extracted from rice husk ash; fabrication and application

MCM-48 mesoporous silica was successfully synthesized from silica gel extracted from rice husk ash and loaded by nickel oxide (Ni2O3). The resulted composite was characterized using X-ray diffraction, scanning electron microscope, and UV-vis spectrophotometer. The role of MCM-48 as catalyst support in enhancing the photocatalytic properties of nickel oxide was evaluated through the photocatalytic degradation of Congo red dye under visible light source. MCM-48 as catalyst support for Ni2O3 shows considerable enhancement in the adsorption capacity by 17% and 29% higher than the adsorption capacity of MCM-48 and Ni2O3, respectively. Additionally, the photocatalytic degradation percentage increased by about 64% relative to the degradation percentage using Ni2O3 as a single component. The adsorption mechanism of MCM-48/Ni2O3 is chemisorption process of multilayer form. The using of MCM-48 as catalyst support for Ni2O3 enhanced the adsorption capacity and the photocatalytic degradation through increasing the surface area and prevents the nickel oxide particles from agglomeration. This was done through fixing nickel oxide particles throughout the porous structure which providing more exposed active adsorption sites and active photocatalyst sites for the incident photons. Based on the obtained results, supporting of nickel oxide particles onto MCM-48 are promising active centers for the degradation of Congo red dye molecules.

Superior removal of Co 2+ , Cu 2+ and Zn 2+ contaminants from water utilizing spongy Ni/Fe carbonate–fluorapatite; preparation, application and mechanism

Spongy Ni/Fe carbonate - fluorapatite was synthesized from natural phosphorite enriched with iron impurities. The morphological, chemical and structural features of the product were estimated using several techniques as XRD, SEM, EDX, and FT-IR. It exhibits spongy structure of nano and micro-pores. The average crystallite size is about 8.27 nm. The suitability of the product for considerable decontamination of Zn2+, Co2+, and Cu2+, ions from water was studied based on several reacting parameters. The equilibrium was attained after 240 min for Zn2+ and Co2+ ions while the adsorption equilibrium of Cu2+ reached after 120 min. The adsorption data for the selected metals was represented well by a pseudo-second-order model which revealed chemisorption uptake. The equilibrium studies were appraised based on traditional models and two advanced models were designed according to the statistical physical theories. The adsorption results highly fitted with Langmuir model followed rather than the other models. This indicated a monolayer adsorption for the metal ions by spongy Ni/Fe carbonate - fluorapatite. The estimated qmax values are 149.25 mg/g, 106.4 mg/g and 147.5 mg/g for the uptake of Zn2+, Co2+, and Cu2+, respectively. Based on monolayer models of one energy and two energies, the number of receptor adsorption sites, number of adsorbed metal ions per active site, the average number of sites which occupied by ions, mono layer adsorption quantity and the adsorption quantity after total saturation were calculated for the first time for such materials.

TiO 2 Nanoribbons/Carbon Nanotubes Composite with Enhanced Photocatalytic Activity; Fabrication, Characterization, and Application

TiO2 nanoribbons (TiO2 NRs) loaded with FeCo-Al2O3 catalyst were synthesized and used as a precursor in the synthesis of TiO2 nanoribbons/carbon nanotubes (TiO2 NRs/CNTs) composite by a chemical vapor deposition (CVD) method. TiO2 NRs and TiO2 NRs/CNTs composite were characterized by XRD, FT-IR, TEM, SEM, EDX and UV-Vis spectrophotometer. The results revealed the formation of TiO2-B and hydrogen titanate nanoribbon like structures by the hydrothermal treatment. After loading TiO2 NRs by FeCo-Al2O3 catalyst and the CVD growth of carbon nanotubes, the synthetic TiO2 nanoribbons converted entirely to TiO2-B nanoribbons with nanopits structure. The composite composed of tube-like nanostructures forming an interlocked network from CNTs and TiO2-B NRs. The composite shows a relatively red-shifted band gap (3.09 eV), broader and stronger UV absorption band relative to TiO2 NRs. The photocatalytic properties of TiO2 NRs and TiO2 NRs/CNTs composite were studied under sunlight irradiation. The photocatalytic degradation of methylene blue (MB) dye was investigated as a function of contact time, dye concentration, and catalyst dose. The kinetics and mechanisms of degradation were discussed. TiO2 NRs/CNTs composite showed higher stability after six runs and 50% shorter irradiation time than TiO2 NRs photocatalyst.

Removal of safranin dye from water using polypyrrole nanofiber/Zn-Fe layered double hydroxide nanocomposite (Ppy NF/Zn-Fe LDH) of enhanced adsorption and photocatalytic properties

Polypyrrole nanofiber/Zn-Fe layered double hydroxide (Ppy NF/Zn-Fe LDH) was synthesized as nanocomposite of enhanced adsorption and photocatalytic properties. The formation of the composite was confirmed by XRD, FT-IR, HSEM, HRTEM, BET surface area and UV-vis spectrophotometer. Ppy NF/Zn-Fe LDH composite exhibits clear enhancing in the specific surface area and obvious reducing in the band gap energy (from 2.8 eV for Zn-Fe LDH to 2.31 eV for the composite). This was reflected in a considerable improvement in the adsorption capacity and photocatalytic removal of safranin dye. The adsorption capacity was enhanced by about 22% higher than Ppy NF and by 31% higher than Zn-Fe LDH. The photocatalytic removal was improved by 41.6% higher than Ppy NF and by about 54% higher than Zn-Fe LDH. The adsorption of safranin dye by the composite is chemisorption adsorption and occurs in a multilayer form. The complete photocatalytic removal of 5 mg/L of safranin dye can be achieved after 120 min illumination time using 0.05 g of the composite as photocatalyst and the best results can be obtained at neutral to alkaline conditions. Realistic application of the composite for the removal of dye from raw water samples revealed the applicability of the product for the purification of tap water, groundwater, and sewage water. Moreover, it can be used for six cycles of safranin dye removal from water. The photocatalytic degradation process appears to be controlled by the created hydroxyl radicals and formed photogenerated holes as the dominant active oxidizing radicals.

Cosmetic and pharmaceutical qualifications of Egyptian bentonite and its suitability as drug carrier for Praziquantel drug

Abstract The aim of this paper is to characterize and evaluate newly discovered bentonite deposits in Egypt for pharmaceutical and cosmetic applications as well as its suitability as carrier for Praziquantel drug. The study was performed for the raw bentonite sample, purified bentonite sample and alkali activated purified bentonite sample. The raw bentonite sample composed mainly of montmorillonite contaminated by little amounts of quartz and calcite, while the purified sample composed of montmorillonite without detected mineral impurities and matches the mineralogical properties of Wyoming bentonite as an international standard. Geochemically, the studied raw and purified samples appear to high purity with a chemical composition close to those of Wyoming bentonite and match the pharmacopeia specifications. The chemical properties in addition to the textural properties of the surface area, porosity, particle size distribution qualify the bentonite products to use as a function in powder, emulsion and creams. Investigation of pharmacopeia properties of pH, sedimentation volume and swelling capacity revealed the suitability of the raw and purified samples for pharmaceutical and cosmetic applications. Moreover, the microbiological tests indicated that the samples free from harmful microbial pathogens. At the optimum conditions of time (240 min), bentonite dose (250 mg) and reaction temperature (60 °C), the obtained encapsulation percentages of Praziquantel drug are 62%, 78.4% and 93.2% for raw bentonite, purified and alkali activated bentonite, respectively. The releasing percentage of the drug using an intestinal buffer at pH 7.4 is more efficient and the maximum obtained values were obtained after 420 min. The obtained releasing values are 71%, 79.2% and 87.4% for raw bentonite, purified bentonite and alkali activated bentonite, respectively Graphical Abstract Figure. No caption available.

Enhanced photocatalytic removal of Safranin-T dye under sunlight within minute time intervals using heulandite/polyaniline@ nickel oxide composite as a novel photocatalyst

Natural zeolite heulandite/polyaniline composite (Hu/PANI) was synthesized for the first time as catalyst support for nickel oxide photocatalyst (Hu/PANI@Ni2O3). The structural, chemical, morphological, textural and optical properties were investigated using different techniques. The synthetic Ni2O3 crystals showed well developed flaky habits with diameter range 200-400 nm and length range 1-4 µm. The estimated band gap energies of Hu/PANI composite and Hu/PANI@Ni2O3 composite are 1.8 eV and 1.46 eV, respectively, which are remarkably smaller than the recorded value for pure nickel oxide. The photocatalytic properties of Hu/PANI@Ni2O3 composite for efficient degradation of safranin-T dye were evaluated under sunlight as a function of irradiation time, initial dye concentration, catalyst mass, solution pH, and the catalyst stability. Hu/PANI@Ni2O3 composite exhibits amazing photocatalytic degradation efficiency for safranin dye, whereas 80%, 98%, and ~ 100% of 5 mg/l dye were removed after only 1 min of solar irradiation using 0.025, 0.03, and 0.035 g of Hu/PANI@Ni2O3, respectively. The higher concentrations of the dye (10-50 mg/L) can be fully removed within minutes by increasing the solution pH or using higher doses from the Hu/PANI@Ni2O3 catalyst. The removal percentage achieved the maximum value at the alkaline conditions. Also, the Hu/PANI@Ni2O3 displayed high stability and remain 84.5% of the initial photocatalytic efficiency after 5 runs. Additionally, the composite can be used effectively in the removal of different types of dyes and mixed dyes within the same time intervals. Thus, loading of nickel oxide onto hybrid Hu/PANI composite as a catalyst support achieved amazing photocatalytic degradation capacity.

Characterization and Beneficiation of Gold Mining By-products as Source of High-Quality Silica for High Technical Applications; Response Surface Studies and Optimization

This paper aims to evaluate and upgrade the quality of quartz mining by-products through acid leaching process. The quartz samples were collected as gold mine by-products from El Sid- Fawakhir gold mine, Qift-Quseir, Eastern Desert, Egypt and characterized using XRF and polarized transmitted optical microscope. The present magnetic mineral impurities were detected using Frantz Isodynamic Tester. Suitability of acid leaching utilizing oxalic acid as an efficient technique for considerable reduction of the associated impurities was evaluated based on Response Surface methodology and face centered central composite design (CCD). The quartz sample was classified as low-quality quartz with low silica content (99.3%) which can’t match the requirements of wide range of applications. The main detected impurities are muscovite, biotite, sericite, pyrite and iron oxide. The present magnetic impurities represent about 2.72% of the total sample. The leaching process at the optimum conditions of temperature, time and oxalic acid concentration removes ∼

Adsorption Removal of Safranin Dye Contaminants from Water Using Various Types of Natural Zeolite

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Adsorption behavior of inorganic- and organic-modified kaolinite for Congo red dye from water, kinetic modeling, and equilibrium studies

36% of the iron. This associated with a clear reduction of other magnetic impurities and noticeable enhancing in the silica content to about 99.56%. Magnetic purification followed by oxalic acid leaching for the quartz samples give better results as the iron content was reduced to about 0.001% and the silica content increased to about 99.9% which match the specifications of most of the typical high technical applications.

Removal of Congo red, methylene blue and Cr(VI) ions from water using natural serpentine

The presented study involved detail investigation for the adsorption properties of three types of natural zeolite (heulandite, clinoptilolite, and phillipsite). The studied zeolite samples were described based on the structural features from the XRD patterns and the surficial morphologies from SEM images. The selected zeolite minerals were applied as adsorbents in the decolorization of safranin-T dye from water. The estimated uptake capacities for safranin revealed the higher capacity of heulandite than clinoptilolite and Phillipsite (heulandite>clinoptilolite>phillipsite). As per the kinetic studies, 240min was detected as the decolorization equilibrium of safranin by heulandite and clinoptilolite; and 480min for phillipsite zeolite. The decolorization mechanisms were classified as chemical processes and represented strongly by Lagergren assumption and Elovich model. Monolayer adsorption form was suggested for the uptake by heulandite and clinoptilolite (Langmuir); and multilayer form was predicted for phillipsite (Freundlich). Neutral to alkaline environment was detected to be the best medium for considerable removal of safranin. Natural zeolite minerals also were applied effectively in safarnin decontamination from raw water and showed effective values in the decolorization of other types of dyes.