M. F. Elkady

Bacillus mojavensis strain 32A, a bioflocculant-producing bacterium isolated from an Egyptian salt production pond

Bacillus mojavensis strain 32A that exhibited 96.11% flocculation efficiency for clay suspensions was selected from other 15 comparative strains. Under growth condition, strain 32A was able to produce 5.2g/L of purified biopolymer. Its constituent was mainly polysaccharide and protein with proportional of 98.4-1.6% respectively. FTIR spectrum was confirming its chemical analysis. This biopolymer attain very fast sedimentation rate. The cost-effective biopolymer and CaCl(2) dosages were 3mg/L and 5 ml/L respectively that posed 89.7% flocculation efficiency. These dosages were suitable only for clay concentrations ≤5g/L. The maximum flocculation efficiency of the biopolymer recorded at pH 1.0 of clay suspension. The too high (>75°C) or too low (<25°C) clay suspension temperature was unfavorable for the biopolymer flocculation performance. The biopolymer solution utilized high thermal stability over the temperature range of 5-60°C. Furthermore, its pH stability recorded at pH range of 5-9.

Formulation of synthesized zinc oxide nanopowder into hybrid beads for dye separation

The sol-gel prepared zinc oxide nanopowder was immobilized onto alginate-polyvinyl alcohol polymer blend to fabricate novel biocomposite beads. Various physicochemical characterization techniques have been utilized to identify the crystalline, morphological, and chemical structures of both the fabricated zinc oxide hybrid beads and their corresponding zinc oxide nanopowder. The thermal stability investigations demonstrate that ZnO nanopowder stability dramatically decreased with its immobilization into the polymeric alginate and PVA matrix. The formulated beads had very strong mechanical strength and they are difficult to be broken up to 1500 rpm. Moreover, these hybrid beads are chemically stable at the acidic media (pH < 7) especially within the pH range of 2–7. Finally, the applicability of the formulated ZnO hybrid beads for C.I. basic blue 41 (BB41) decolorization from aqueous solution was examined.

The use of bioflocculant and bioflocculant-producing Bacillus mojavensis strain 32A to synthesize silver nanoparticles

It is preferable to use an organism to produce more than one product at the same time. So, the aim of this study was to investigate the ability of bioflocculant-producing Bacillus mojavensis strain 32A as a nanosilver synthesizer beside bioflocculant production. To achieve this target, three media, nutrient broth, bioflocculant-producing medium, and pure bioflocculant, were tested. Produced nanosilver was characterized by UV-vis, XRD, and TEM. In all cases, the results demonstrated that UV-vis showed a peak at ∼420 nm corresponding to the plasmon absorbance of nanosilver. XRD spectrum exhibited 2θ values corresponding to the silver nanocrystal that is produced in hexagonal and cubic crystal configurations. TEM confirmed formation, size, shape, and morphologies of nanosilver particles. The results emphasized that purified bioflocculant has the ability to produce anisotropy clusters of nanosilver ranging in size from 6 to 72 nm proving that the bioflocculant functioned as reducing and stabilizing agent in nanosilver synthesis.

Construction of Zinc Oxide into Different Morphological Structures to Be Utilized as Antimicrobial Agent against Multidrug Resistant Bacteria.

Nano-ZnO has been successfully implemented in particles, rods, and tubes nanostructures via sol-gel and hydrothermal techniques. The variation of the different preparation parameters such as reaction temperature, time, and stabilizer agents was optimized to attain different morphological structures. The influence of the microwave annealing process on ZnO crystallinity, surface area, and morphological structure was monitored using XRD, BET, and SEM techniques, respectively. The antimicrobial activity of zinc oxide produced in nanotubes structure was examined against four different multidrug resistant bacteria: Gram-positive (Staphylococcus aureus and Bacillus subtilis) and Gram-negative (Escherichia coli and Pseudomonas aeruginosa) strains. The activity of produced nano-ZnO was determined by disc diffusion technique and the results revealed that ZnO nanotubes recorded high activity against the studied strains due to their high surface area equivalent to 17.8 m2/g. The minimum inhibitory concentration (MIC) of ZnO nanotubes showed that the low concentrations of ZnO nanotubes could be a substitution for the commercial antibiotics when approached in suitable formula. Although the annealing process of ZnO improves the degree of material crystallinity, however, it declines its surface area and consequently its antimicrobial activity.

Basic Violet Decolourization Using Alginate Immobilized Nanozirconium Tungestovanadate Matrix as Cation Exchanger

As an innovative cation exchange material, nanozirconium tungestovanadate prepared using homogeneous precipitation technique was immobilized into alginate matrix and evaluated for cationic dye decolourization. Physicochemical properties of the prepared composite material were examined to determine its crystallinity, morphology, and ion exchange capacity. The SEM and TEM images of the prepared zirconium tungestovanadate identified that it was prepared in homogeneous structure with spherical shape in average diameter 22 nm. However, the optical microscope image of the composite matrix confirms the good distribution of nanozirconium tungestovanadate into the polymeric matrix. Batch technique was utilized to test the cation exchange efficiency of the prepared composite material toward C.I. basic violet 16 dye decolourization. The optimum immobilized dosage from nanozirconium tungestovanadate into the polymeric matrix to achieve 99% dye decolourization from 50 ppm initial dye concentration was recorded as 8 g/L. The dye sorption process onto the prepared material is described as an endothermic process. The dye sorption process at equilibrium was following both Langmuir and Freundlich isotherm models. The kinetic sorption behaviour of dye onto the composite matrix is correlated to pseudo-second-order equation model.

Adsorption Profile of Basic Dye onto Novel Fabricated Carboxylated Functionalized Co-Polymer Nanofibers

Acrylonitrile-Styrene co-polymer was prepared by solution polymerization and fabricated into nanofibers using the electrospinning technique. The nanofiber polarization was enhanced through its surface functionalization with carboxylic acid groups by simple chemical modification. The carboxylic groups’ presence was dedicated using the FT-IR technique. SEM showed that the nanofiber attains a uniform and porous structure. The equilibrium and kinetic behaviors of basic violet 14 dye sorption onto the nanofibers were examined. Both Langmuir and Temkin models are capable of expressing the dye sorption process at equilibrium. The intraparticle diffusion and Boyd kinetic models specified that the intraparticle diffusion step was the main decolorization rate controlling the process.

Preparation and characterization of imino diacetic acid functionalized alginate beads for removal of contaminants from waste water: I. methylene blue cationic dye model

Abstract This study deals with the development of a clean and safe process for water pollution remediation. We studied the potential use of Imino Diacetic Acid (IDA) activated calcium alginate beads for removal of cationic dyes from colored effluents in dynamic batch mode. Methylene blue (MB) has been chosen as a dye model for the study. The parameters that affect the beads surface modification process such as ρ-benzoquinone (PBQ) and IDA concentration, reaction time, pH, temperature and finally cross linking time in calcium chloride solution were studied. Maximum percents of dye removal are about 65% and 90% were achieved at initial MB concentration of 50 mg l−1 after 60 min of adsorption at temperature (22 ± 1°C) for calcium alginate and IDA activated calcium alginate beads respectively. Surface modification reduces the competitive action of calcium ions especially at high bead’s crosslinking degree. Removal percentage was doubled using modified alginate beads cross linked for 120 min at 2% CaCl2. In co...

Sorption Profile of Phosphorus Ions onto ZnO Nanorods Synthesized via Sonic Technique

High surface area zinc oxide material in nanorod morphological structure was synthesized using an ultrasonic technique in the presence of polyvinyl pyrrolidone as stabilizing agent. The crystallite, morphology, and surface area of the prepared white powder material were identified using XRD, SEM, and BET techniques, respectively. X-ray analysis confirms the high purity of synthesized ZnO. The evaluated specific surface area of prepared ZnO was 16.7 m2/g; this value guarantees high efficiency for water purification. The feasibility of synthesized ZnO nanorods for phosphorus sorption from aqueous solution was established using batch technique. Nano-zinc oxide exhibits high efficiency for phosphorus removal; the equilibrium state was recorded within 90 minutes. The most effective hydrogen ion concentration of the polluted solution was recorded at pH = 1 for phosphorus decontamination. The equilibrium of phosphorus sorption onto ZnO nanorods was well explained using both Langmuir and Temkin isotherm models. The calculated maximum monolayer sorption capacity was 89 mg/g according to Langmuir isotherm at 27°C. In order to explain the phosphorus sorption mechanism onto the prepared ZnO nanorods, three simplified kinetic models of pseudo-first order, pseudo-second order, and intraparticle diffusion rate models were tested. Kinetics was well fitted by pseudo-second order kinetic model with a contribution of intraparticle diffusion.

Immobilization of Magnetic Nanoparticles onto Amine-Modified Nano-Silica Gel for Copper Ions Remediation

A novel nano-hybrid was synthesized through immobilization of amine-functionalized silica gel nanoparticles with nanomagnetite via a co-precipitation technique. The parameters, such as reagent concentrations, reaction temperature and time, were optimized to accomplish the nano-silica gel chelating matrix. The most proper amine-modified silica gel nanoparticles were immobilized with magnetic nanoparticles. The synthesized magnetic amine nano-silica gel (MANSG) was established and characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), Fourier transform infrared (FTIR), thermal gravimetric analysis (TGA), differential scanning calorimetry (DSC) and vibrating sample magnetometry (VSM). The feasibility of MANSG for copper ions’ remediation from wastewater was examined. MANSG achieves a 98% copper decontamination from polluted water within 90 min. Equilibrium sorption of copper ions onto MANSG nanoparticles obeyed the Langmuir equation compared to the Freundlich, Temkin, Elovich and Dubinin-Radushkevich (D-R) equilibrium isotherm models. The pseudo-second-order rate kinetics is appropriate to describe the copper sorption process onto the fabricated MANSG.

Investigation of the decolorization efficiency of two pin-to-plate corona discharge plasma system for industrial wastewater treatment

In this article, a dual pin-to-plate high-voltage corona discharge system is introduced to study experimentally the gap distance, the contact time, the effect of pin and plate materials, the thickness of ground plate and the conductivity on the amount of Acid Blue 25 dye color removal efficiency from polluted water. A study for the optimum air gap distance between dual pin and surface of Acid Blue 25 dye solution is carried out using 3D-EM simulator to find maximum electric field intensity at the tip of both pins. The outcomes display that the best gap for corona discharge is approximately 5 mm for 15-kV source. This separation is constant during the study of other factors. In addition, an investigation of the essential reactive species responsible for oxidation of the dye organic compounds (O3 in air discharge, O3 in water, and H2O2) during the experimental time is conducted. Three various materials such as: stainless steel, copper and aluminum are used for pins and plate. The maximum color removal efficiencies of Acid Blue 25 dyes are 99.03, 82.04, and 90.78% after treatment time 15 min for stainless steel, copper, and aluminum, respectively. Measurement results for the impact of thickness of an aluminum ground plate on color removal competence show color removal efficiencies of 86.3, 90.78, and 98.06% after treatment time 15 min for thicknesses of 2, 0.5, and 0.1 mm, respectively. The increasing of the solution conductivity leads to the reduction of decolorization efficiency. A kinetic model is used to define the performance of corona discharge system. The models of pseudo-zero-order, pseudo-first-order, and pseudo-second-order reaction kinetics are utilized to investigate the decolorization of Acid Blue 25 dye. The rate of degradation of Acid Blue 25 dye follows the pseudo-first-order kinetics in the dye concentration.