Poly(Acrylic Acid) Grafted Sodium Alginate Di-Block Hydrogels as Efficient Biosorbents; Structure-Property Relevance

Naturally-based poly(acrylic acid) grafted sodium alginate di-block hydrogels were investigated as high efficiency biosorbents for copper(II) ion. The grafted di-block hydrogel was characterized using FTIR, TGA and SEM techniques. Blank and immobilized algal biosorbent beads formed via 2.0% (w/w) calcium ions were also investigated. Batch adsorption experiments revealed optimal pH dependence of copper(II) ion biosorption at pH 5.5 with high efficient copper(II) ion uptake of 98.5 mg/g. The dynamics studies showed that the high efficiency copper(II) ion biosorption followed pseudo-second order kinetics with significant contribution of intraparticle diffusion mechanism. The equilibrium data fitted to Langmuir, Freundlich, and Dubinin–Radushkevich (D–R) adsorption isotherm models. Thermodynamics parameters for copper(II) biosorption on blank and immobilized algal beads depicted the spontaneous nature of the biosorption process. Such high efficiency, feasibility, simplicity, and low cost properties adapt the di-block biosorbent to be the next generation promising biosorbents for water decontamination and to help in the recovery of the missing ecologic harmony.     

Assessment of elemental distribution and heavy metals contamination in phosphate deposits: potential health risk assessment of finer-grained size fraction

The concentrations and chemical distributions of heavy metals (Cd, Cr, Ni, Zn, U, and V) in the Al-Jiza phosphate ores were investigated. Typically, the mean concentration values of Cd, Cr, Ni, U, and Zn are 15 ± 8, 109 ± 21, 34 ± 6, 211 ± 55, 142 ± 55, and 161 ± 57 mg kg^?1, respectively. On the other hand, the encountered average concentration values of Cd, Cr, Ni, Zn, U, and V in the phosphate dust particles (<0.053) were found to be 22 ± 5, 179 ± 5, 67 ± 11, 441 ± 14, 225 ± 58, and 311 ± 9 mg kg^?1, respectively. The contamination factors of U and Cr are greater than 1, indicating that these heavy metals could be potentially hazardous, if released to the environment. Multivariate statistical analysis allowed the identification of three main factors controlling the distribution of these heavy metals and the other chemical constituents. The extracted factors are as follows: francolite mineral factor, clay minerals factor, and diagenesis factor. Health risk assessments of non-cancerous effects in finer-grained size fraction that might be caused by contamination with the heavy elements have been calculated for both children and adults. The risk assessments in case of children for non-cancerous effects showed that U has values greater than the safe level of hazard index (HI = 1). In case of adults, the value of risk for U is also higher as compared to those of Cd, Ni, Cr, and Zn where it lies within the safe range of hazard index (HI < 1). Child health risk assessment indicates that children are more vulnerable to contaminants from phosphate mining than adults.     

Comparison of steel,aluminum and composite bonnet in terms of pedestrian head impact

Material selection for automotive closures is influenced by different factors such as cost, weight and structural performance. Among closures, the automotive bonnet must fulfill the requirements of pedestrian safety which is evaluated by child and adult headform impactors. The mechanisms of injury are complex, therefore; the Head Injury Criterion (HIC) which shows a measure of the likelihood of head injury arising from an impact is developed. HIC includes the effects of head acceleration and the duration of the acceleration.In this paper a new finite element model has been developed which is capable to simulate head impact phenomenon between headform impactors and composite bonnet. Then the behavior of three identical bonnets made of steel, aluminum and composite have been investigated by the developed model. It is shown that the energy absorption of aluminum bonnet is smaller than steel and composite ones and for keeping the aluminum bonnet at the same level of stiffness, it is necessary to increase the thickness. Therefore, the aluminum bonnet needs a larger space between the bonnet and the parts in the engine compartment. It is shown that although the displacement of headform for composite bonnet is more than that of steel and aluminum ones, but the amount of HIC’s, which are measured at the collision points are much less than those measured at the same collision points for steel and aluminum bonnets.In addition the comparison of three bonnets of the different materials has been done to highlight cost, weight, and structural performance issues.     

Optimization of Xanthan Gum/Poly(acrylic acid)/Cloisite 15A Semi-IPN Hydrogels for Heavy Metals Removal

Journal of Polymers and the Environment - Semi-interpenetrating networks (semi-IPNs) of Xanthan gum/poly (acrylic acid) containing Cloisite 15A were prepared via radical polymerization using a...     

Characterization of Active Polybutylene Succinate Films Filled Essential Oils for Food Packaging Application

Journal of Polymers and the Environment - The development of active packaging for food applications have been increasingly favorable in publicity, industry, and research field, by attributing to...     

Epoxidised Natural Rubber Filled Spent Coffee Ground Green Biocomposites

Journal of Polymers and the Environment - This study investigates the influence of spent coffee (SC), and potassium hydroxide (KOH) modified spent coffee (ACT-SC) as fillers on the mechanical and...     

Effect of Curing Temperature on Mechanical Properties of Bio-phenolic/Epoxy Polymer Blends

Journal of Polymers and the Environment - Nowadays, researchers continue studies for alternative materials to replace the redundant petroleum-based products. The combination of various polymer...     

Bioremediation perspectives and progress in petroleum pollution in the marine environment: a review

Environmental Science and Pollution Research - The marine environment is often affected by petroleum hydrocarbon pollution due to industrial activities and petroleum accidents. This pollution has...     

A convolutional neural network approach for detection of E. coli bacteria in water

Environmental Science and Pollution Research - The detection of Escherichia coli bacteria is essential to prevent health diseases. According to the laboratory-based methods, 12–48 h is...     

Design of a hybrid ANN multi-objective whale algorithm for suspended sediment load prediction

Environmental Science and Pollution Research - There is a need to develop an accurate and reliable model for predicting suspended sediment load (SSL) because of its complexity and difficulty in...