Evaluation of copper adsorption from industrial wastewater using sewage sludge ash

A BSTRACT The objective of this research work is to highlight the importance of using waste material such as sewage sludge, as a starting material for adsorption of heavy metals. Sludge incineration can help to stabilize and reduce the volume of sewage sludge; and the resultant ash (SSA) has been considered as an adsorbent for the removal of heavy metals from industrial waste water. In batch process, the effect of environmental condition such as adsorbate concentration (12.5, 25, 50 and 100 mg/L) was studied to evaluate the removal efficiency of SSA. Also, the effects of weight ratio of SSA (0.1, 0.5, 1 and 3 mg/100 mL), agitation speed (60, 150, 200 and 250 rpm), mesh size of adsorbent (60, 65 and 90 µm), temperature (40, 50 and 60 °C) and contact time (10, 20, 30, 60, 110 and 180 min), on the removal of copper ions were investigated. The optimized experimental conditions were used for the removal of copper ions from wastewater obtained from El-Sewedy cables industry. Experimental investigations indicated that at low solute concentration of 25 mg/L and high agitation speed of 250 rpm, the removal efficiency of copper ions by SSA reached 98% with the SSA dosage equal or higher than 3 g/100 mL. Adsorption isotherm studies indicated that Langmuir model described the experimental data with R 2 values greater than 0.994. The study highlighted the ability of SSA for the removal of copper ions from industrial wastewater

Purtscher’s retinopathy: A case of severe bilateral visual loss due to chest compression

We report a case of bilateral Purtscher’s retinopathy in a young man following a motor vehicle rollover accident. Decreased vision was noticed on the fifth day following the trauma. Visual acuity in the right eye was close counting finger, and left eye, counting finger one meter. There was no evidence of direct ocular, head or facial trauma. Purtscher flecken, pre-retinal and retinal hemorrhages were present in both eyes. The right eye showed optic disc edema and more extensive areas of capillary dropout. Patient was treated with intravenous methyl prednisolone. After 5 weeks the right eye vision improved to counting finger one meter and left eye improved to 6/18. Early detection, proper documentation and treatment of the underlying causes in these cases is very important in order to avoid medico-legal pitfalls

Application of contact stabilization activated sludge for enhancing biological phosphorus removal (EBPR) in domestic wastewater

The experiment has been performed in order to investigate the effect of using contact stabilization activated sludge as an application of enhancing biological phosphorous removal (EBPR) by using contact tank as a phosphorus uptake zone and using thickening tank as a phosphorus release zone. The study involved the construction of a pilot plant which was setup in Quhafa waste water treatment plant (WWTP) that included contact, final sedimentation, stabilization and thickening tanks, respectively with two returns sludge in this system one of them to contact tank and another to stabilization tank. Then observation of the uptake and release of total phosphorus by achievement through two batch test using sludge samples from thickener and final sedimentations. Results showed the removal efficiencies of COD, BOD and TP for this pilot plant with the range of 94%, 85.44% and 80.54%, respectively. On the other hand the results of batch tests showed that the reason of high ability of phosphorus removal for this pilot plant related to the high performance of microorganisms for phosphorus accumulating. Finally the mechanism of this pilot plant depends on the removal of the phosphorus from the domestic waste water as a concentrated TP solution from the supernatant above the thickening zone not through waste sludge like traditional systems

Effects of nano zero valent iron and entrapped nano zero valent iron in alginate polymer on poly aromatic hydrocarbons removal

A BSTRACT Modern countries deal with the different types and variety of industries. Large number of these industries depends on water and mainly causes water contaminations. One of these contaminants is poly aromatic hydrocarbons (PAHs). This study successfully used magnetic nano sorbent especially nano zero-valent iron (nZVI) and encapsulated nZVI in alginate polymer to reduce hydrocarbons contaminations in water by studying the effects of contact time, adsorbent dose, pH, stirring rate, initial PAHs concentration and temperature. Batch study was conducted and removal efficiency between 43% and 56 % was achieved for different PAHs concentrations (222, 74, and 37 µg/L) with 0.2 g of nZVI/L pH 7, stirring rate 100 rpm, 30 o C and 30 min contact time. On the other hand the encapsulated nZVI in alginate biopolymer was also studied under the same conditions. The encapsulation process was mainly depended on the quantity of the nZVI entrapped in alginate biopolymer. The quantity of nZVI used in this research was 4 g/L of alginate gel matrix. Removal efficiency between 50 and 75% was achieved for different PAHs concentrations (222, 74, and 37 µg/L) with 20 g/L Ca-alginate/nZVI, pH 7, stirring rate 100 rpm, 30 o C and 30 min contact time. The results indicated that alginate increase stability of nZVI against oxidation and increase PAHs removal efficiency. KEYWORDS alginate biopolymer; encapsulate nZVI/alginate; magnetic nanosorbents; nano zero valent iron; poly aromatic hydrocarbons remova

Highly porous PtPd nanoclusters synthesized via selective chemical etching as efficient catalyst for ethanol electro-oxidation

Direct ethanol fuel cells (DEFCs) have received great interest owing to their high power density and environmental friendness. Nevertheless, the designing of active, durable, and efficient anode for DEFCs is a profound challenge. In this context, we reported the synthesis of PtPd porous nanoclusters (PtPd PNCs) as electrocatalyst for ethanol oxidation reaction (EOR). This was implemented through two-step synthesis. Firstly, ternary AgPtPd nanodendrites (NDs) were synthesized via ultrasound-assisted co-reduction of the metal precursors using ascorbic acid (AA) as a mild reductant and Pluronic F127 as structure-directing agent. Thereafter, PtPd PNCs were created by selective chemical etching of AgPtPd nanocrystals in 1 M HNO3. The textural properties, morphology, and elemental composition of the studied electrocatalysts were investigated, and their catalytic activities towards ethanol electrooxidation were examined. PtPd PNCs revealed a high surface area of 83.0 m2 g−1 and high porosity compared to its counterparts. Additionally, it depicted enhanced catalytic performance towards ethanol electrooxidation in 1 M KOH with mass activity of 1.8 A mg−1 compared to PtPd NDs (0.97 A mg−1), Pt NDs (0.51 A mg−1), and Pt/C (0.33 A mg−1). The enhanced catalytic performance of PtPd PNCs was ascribed to high surface area, high porosity, and increased active sites.Scopu