An-Najah Staff

Different pollutants from industries leach every day to soil and ground waters without treatment. The product N,N-bis (3,5-Dimethylpyrazol-1-yl methyl)-3-aminopropyl Polysiloxane (Si-C3H6NPz2) was successfully prepared. The FTIR results confirmed that the dimethylpyrazole units have been immobilized onto the surface of the modified silica gel. The adsorption experiments were conducted for a wide range of solution pH, adsorbent dosage, temperature, initial concentration and contact time. It was observed that the percentage removal of methylene blue dye decreased with an increase initial concentration and temperature while it increased with increase in solution pH, contact time and adsorbent dose. Over 82% removal efficiency of methylene blue dye was achieved after 180 min at solution pH around 10, 20°C temperature, 0.25 g weight of dose and initial concentration of 15 mg/L of 50mL MB dye solution.  Negative ∆G° values (-17.17 to -17.25 KJ/mol) indicate that the adsorption is favorable and spontaneous at these temperatures. The negative value of ∆H° (-16.66 KJ/mol) reflects an exothermic adsorption and indicates that the adsorption is favored at low temperature. The value of ∆H° was higher than those corresponding to physical adsorption. This would suggest that the adsorption process is chemical in nature. The small positive value of ∆S° (+1.78 J/mol.K) suggests that some structural changes occur on the adsorbent and the randomness at the solid/liquid interface in the adsorption system increases during the adsorption process. The results of the present study show that the prepared compound has a negative biological activity against Pseudomonas aeruginosa, Staphylococcus aurous, and Escherichia coli. 

In this work, different treatment methods for wastewater from textile washing operations in the Palestinian territories were studied. The goal of the treatment process was to enable the textile industry to reuse the wastewater in textile washing through simple, efficient, and cost-effective methodologies. Actual textile wastewater samples from local textile factories were used and were found to be highly polluted. The study focused on three main processes; sedimentation, coagulation, and adsorption. While sedimentation was found to reduce the total suspended solids (TSS) of the wastewater, coagulation had the additional advantages of lowering the chemical oxygen demand (COD) and achieving higher filtration rates. Four coagulants were tested, ferric chloride, ferrous sulfate plus lime, aluminum sulfate, and aluminum sulfate plus lime. While ferric chloride failed to perform effectively as a coagulant, the other three coagulants were fairly effective. Finally, to further lower the COD of post-coagulation treated water, adsorption using activated carbon was studied. It was found that carbon was effective in reducing the COD of the wastewater using reasonable quantities, where up to 98% COD reduction was achieved using 6 g carbon/L.

The increase in demand for the limited raw water resources in the Palestinian Territories has led to the proposals for use of treated wastewater as one alternative for alleviating water shortages and for optimizing the use of water resources. Wastewater reuse is a multi-discipline and important element of water resources development. Wastewater usage releases high quality water for drinking and other purposes. Quantitative, economic, and social aspects related to wastewater reuse in the West Bank are discussed. Through analyses of the estimated cost and expected water quantities, the paper investigates the economic feasibility of wastewater reuse. Social acceptance is elicited by means of questionnaires, which have been applied to farmers and inhabitants in different areas of the West Bank. Wastewater reuse can compensate for about 10 percent of irrigated agriculture, which contributes 35 percent of the total value of the Palestinian agricultural sector. The paper presents an analysis of the main aspects of wastewater reuse and defines an approach to the beneficial use of wastewater as a component that should be considered in the strategy for the overall management of water resources in the Palestinian Territories.

Membrane fouling is one of the main constraints of the wide use of membrane bioreactor (MBR) technology. The biomass in MBR systems includes extracellular polymeric substances (EPS), metabolic products of active microbial secretion that adversely affect the membrane performance. Solids retention time (SRT) in the MBR is one of the most important parameters affecting membrane fouling in MBR systems, where fouling is minimized at optimal SRT. Among the operating parameters in MBR systems, SRT is known to strongly influence the ratio of proteins to polysaccharides in the EPS matrix. In this study, we have direct evidence for changes in EPS adherence and viscoelastic properties due to changes in the sludge removal rate that strongly correlate with the membrane fouling rate and EPS composition. EPS were extracted from a UF membrane in a hybrid growth MBR operated at sludge removal rates of 59, 35.4, 17.7, and 5.9 L day^-1 (corresponding SRT of 3, 5, 10, and 30 days, respectively). The EPS adherence and adsorption kinetics were carried out in a quartz crystal microbalance with dissipation monitoring (QCM-D) technology in several adsorption measurements to a gold sensor coated with Polyvinylidene Fluoride (PVDF). EPS adsorption to the sensor surface is characterized by a decrease of the oscillation frequency and an increase in the dissipation energy of the sensor during parallel flow of aqueous media, supplemented with EPS, above the sensor surface. The results from these experiments were further modeled using the Voigt based model, in which the thickness, shear modulus, and shear viscosity values of the adsorbed EPS layers on the PVDF crystal were calculated. The observations in the QCM-D suggested that the elevated fouling of the UF membrane is due to higher adherence of the EPS as well as reduction in viscosity and elasticity of the EPS adsorbed layer and elevation of the EPS fluidity. These results corroborate with confocal laser scanning microscopy (CLSM) image analysis showing thicker EPS in close proximity to the membrane surface operated at reactor conditions which induced more fouling at elevated sludge removal rates.

Removal of copper from polluted water by plant leaves was studied using 15 species. Copper was recovered in variable percentages depending on the species and pH value of the solution. Copper recovery from a 20 mg/L copper solution ranged between 88% (in poplar leaves) and 33% (in oak leaves). For all leaves studied, maximum copper recoveries were found to be between pH 4 and 6 depending on the plant species. At pH 2 the copper was not removed by the plant leaves studied. Adsorption was suggested as the main mechanism for the reaction between copper ions and plant leaves with a reaction order equal to one.

Pharmaceutical pollution is one of the most serious types of environmental pollution attracting increasing attention and leading research studies in recent years. Because of their great impact on aquatic life, soil and underground water as emerging aquatic micro pollutants, it’s possible that they have been affecting the ecological system. In this study, two antibacterials, oxytetracycline and doxycycline were selected as examples of pharmaceuticals that are released into the environment and have major health impacts on our life, such as allergic reactions in the body, hives; difficulty in breathing. Both are marketed in Palestine either for the human pharmaceutical industry or the veterinary one. In this research, the adsorption behavior of both pharmaceuticals on soil, the effect of organic matter, the effect of magnesium chloride hepta hydrate addition on polluted soil, and their effect on characteristics of underground water, were all studied using the UV-Vis spectrophotometer. The results showed that increasing organic matter increases the adsorption of oxytetracycline more than doxycycline, and that the composition of oxytetracycline complex with magnesium ion was more stable than that of doxycycline complex with magnesium. The study also revealed a higher concentration of doxycycline in leachate water from the soil than that of oxytetracycline, because doxycycline has higher solubility in water. It also showed a decrease in the concentrations for both substances over time in leachate water due to degradation. The degradation of both pharmaceuticals in soil and water would be produced by other substances which may be harmful, as the threat of their presence in the soil and groundwater would increase the resistance of bacteria in the soil. In other words, that would affect the natural properties of soil and groundwater, as well.

Iron oxide nanoadsorbents are cost-effective adsorbents that provide high adsorption capacity, rapid adsorption rate and simple separation and regeneration. In this study, Fe3O4 nanoadsorbents have been employed for the removal of Pb(II) ions from aqueous solutions by a batch-adsorption technique. The effects of contact time, initial concentration of Pb(II) ions, temperature, solution pH and coexisting ions on the amount of Pb(II) adsorbed have been investigated. Pb(II) adsorption was fast, and equilibrium was achieved within 30 min. The amount of Pb(II) adsorbed increased as temperature increased, suggesting an endothermic adsorption. The optimal pH value for Pb(II) adsorption was around 5.5. Furthermore, the addition of coexisting cations such as Ca2+, Ni2+, Co2+, and Cd2+ has no remarkable influence on Pb(II) removal efficiency. The adsorption equilibrium data fitted very well to Langmuir and Freundlich adsorption isotherm models. The thermodynamics of Pb(II) adsorption onto the Fe3O4 nanoadsorbents indicated that the adsorption was spontaneous, endothermic and physical in nature. The desorption and regeneration studies have proven that Fe3O4 nanoadsorbents can be employed repeatedly without impacting its adsorption capacity.