Treatment of industrial wastewater containing Congo Red and Naphthol Green B using low-cost adsorbent

The present work investigates the potential use of metal hydroxides sludge (MHS) generated from hot dipping galvanizing plant for adsorption of Congo Red and Naphthol Green B dyes from aqueous solutions. Characterization of MHS included infrared and X-ray fluorescence analysis. The effect of shaking time, initial dye concentration, temperature, adsorbent dosage and pH has been investigated. The results of adsorption experiments indicate that the maximum capacity of Congo Red and Naphthol Green B dyes at equilibrium (q _e) and percentage of removal at pH 6 are 40 mg/g, 93 %, and 10 mg/g, 52 %, respectively. Some kinetic models were used to illustrate the adsorption process of Congo Red and Naphthol Green B dyes using MHS waste. Thermodynamic parameters such as (ΔG, ΔS, and ΔH) were also determined.     

Enhanced desorption of RDX from granular activated carbon.

Several methods (cosolvents, surfactants, and cyclodextrins) were compared for improving desorption of a high explosive, RDX, from granular activated carbon (GAC). In batch desorption tests, 3% of the adsorbed RDX (initially 71.1 mg RDX/g GAC) was desorbed by water over 11 days, compared to 92.6% desorption by 100% ethanol. Solutions of ethanol or methanol in water also effectively desorbed RDX, although methanol was somewhat less effective than ethanol. Sodium dodecyl sulfate desorbed as much as 70% of the adsorbed RDX, while the non-ionic surfactants Tween 80, Triton X-100, and Brij 30 desorbed as much as 42 to 51% of the RDX. In continuous flow column tests, GAC was partially regenerated. One-half of the adsorbed RDX was desorbed by 2100 bed volumes (BV) of 10% ethanol, compared to the 22 500 BV of buffered water. Column modeling indicated that competitive adsorption and altered equilibrium conditions combined to enhance RDX desorption.     

Heavy Metal Concentrations in Sea Urchin Tissues From Egypt,Ireland and United Kingdom

Abstract

Sea urchins (Paracentrotus lividus) were collected from the Mediterranean coast off Alexandria, Egypt and the Atlantic coast of Ireland to the west of Galway. Samples of another urchin species, Psammechinus miliaris, were collected from the entrance to Southampton Water, U.K. Both the Alexandria coast and Southampton Water receive domestic and industrial waste water inputs whilst the western Irish coast is relatively unpolluted.

Sampled animals were dissected to separate coelomic fluids, Aristotle's lantern, gonads and tissue (digestive tract plus connective tissue). the concentrations of heavy metals (cadmium, copper, lead, nickel and zinc) in the different parts were measured using flame atomic absorption spectroscopy.

Many levels of heavy metals in the different parts were similar in specimens taken across the wide range of sites and the two species. A notable exception was the high level of copper (33 μg g^?1 dry wt.) and zinc 328 μg g^?1? dry wt.) in urchin tissue from Southampton Water.

The metal concentrations in the gonads of Paracentrotus lividus are of particular interest because of human consumption of this species. the highest levels of copper (3.3–5.2 g^?1? dry wt.) and zinc (74–181 μ g^?1? dry wt.) dry wt.) in gonads were found in the samples from Egypt. Data from this study are compared with other results reported from the Mediterranean.

A simple, short term, elevated water column copper uptake experiment was undertaken with Paracentrotus lividus which showed an increase in gonad concentrations of this element.     

Exogenously applied calcium alleviates cadmium toxicity in Matricaria chamomilla L. plants

Cadmium (Cd) toxicity in plants leads to serious disturbances of physiological processes, such as inhibition of chlorophyll synthesis, oxidative injury to the plant cells and water and nutrient uptake. Response of Matricaria chamomilla L. to calcium chloride (CaCl₂) enrichment in growth medium for reducing Cd toxicity were studied in this study. Hydroponically cultured seedlings were treated with 0, 0.1, 1, and 5 mM CaCl₂, under 0, 120, and 180 μM CdCl₂ conditions, respectively. The study included measurements pertaining to physiological attributes such as growth parameters, Cd concentration and translocation, oxidative stress, and accumulation of phenolics. Addition of CaCl₂ to growth media decreased the Cd concentration, activity of antioxidant enzymes, and reactive oxygen species accumulation in the plants treated with different CdCl₂, but increased the growth parameters. Malondialdehyde and total phenolics in shoots and roots were not much affected when plants were treated only with different CaCl₂ levels, but it showed a rapid increase when the plants were exposed to 120 and 180 CdCl₂ levels. CaCl₂ amendment also ameliorated the CdCl₂-induced stress by reducing oxidative injury. The beneficial effects of CaCl₂ in ameliorating CdCl₂ toxicity can be attributed to the Ca-induced reduction of Cd concentration, by reducing the cell-surface negativity and competing for Cd²⁺ ion influx, activity enhancement of antioxidant enzymes, and biomass accumulation.     

Development of a waste management protocol based on assessment of knowledge and practice of healthcare personnel in surgical departments

Background:Good healthcare waste management in a hospital depends on a dedicated waste management team, good administration, careful planning, sound organization, underpinning legislation, adequate financing, and full participation by trained staff. Hence, waste management protocols must be convenient and sensible.Aim of study:To assess the knowledge and practice related to waste management among doctors, nurses, and housekeepers in the surgical departments at Al-Mansoura University Hospital, and to design and validate a waste management protocol for the health team in these settings.Subjects and methods:This cross-sectional study was carried out in the eight surgical departments at Al-Mansoura University Hospital. All health care personnel and their assistants were included: 38 doctors, 106 nurses, and 56 housekeepers. Two groups of jury were included for experts’ opinions validation of the developed protocol, one from academia (30 members) and the other from service providers (30 members). Data were collected using a self-administered knowledge questionnaire for nurses and doctors, and an interview questionnaire for housekeepers. Observation checklists were used for assessment of performance. The researchers developed the first draft of the waste management protocol according to the results of the analysis of the data collected in the assessment phase. Then, the protocol was presented to the jury group for validation, and then was implemented.Results:Only 27.4% of the nurses, 32.1% of the housekeepers, and 36.8% of the doctors had satisfactory knowledge. Concerning practice, 18.9% of the nurses, 7.1% of the housekeepers, and none of the doctors had adequate practice. Nurses’ knowledge score had a statistically significant weak positive correlation with the attendance of training courses (r = 0.23, p < 0.05). Validation of the developed protocol was done, and the percent of agreement ranged between 60.0% and 96.7% for the service group, and 60.0% and 90.0% for the academia group.Conclusion and recommendations:The majority of the doctors, nurses, and housekeepers have unsatisfactory knowledge and inadequate practice related to health care waste management. The knowledge among nurses is positively affected by attendance of training programs. Based on the findings, a protocol for healthcare waste management was developed and validated. It is recommended to implement the developed waste management protocol for the surgical departments in the designed hospital, with establishment of waste management audits.     

Adsorption properties of kaolinite-based nanocomposites for Fe and Mn pollutants from aqueous solutions and raw ground water: kinetics and equilibrium studies

Raw kaolinite was used in the synthesis of metakaolinite/carbon nanotubes (K/CNTs) and kaolinite/starch (K/starch) nanocomposites. Raw kaolinite and the synthetic composites were characterized using XRD, SEM, and TEM techniques. The synthetic composites were used as adsorbents for Fe and Mn ions from aqueous solutions and natural underground water. The adsorption by the both composites is highly pH dependent and achieves high efficiency within the neutral pH range. The experimental adsorption data for the uptake of Fe and Mn ions by K/CNTs were found to be well represented by the pseudo-second-order kinetic model rather than the intra-particle diffusion model or Elovich model. For the adsorption using K/starch, the uptake results of Fe ions was well fitted by the second-order model, whereas the uptake of Mn ions fitted well to the Elovich model rather than pseudo-second-order and intra-particle diffusion models The equilibrium studies revealed the excellent fitting of the removal of Fe and Mn ions by K/CNTs and Fe using K/starch with the Langmuir isotherm model rather than with Freundlich and Temkin models. But the adsorption of Mn ions by K/starch is well fitted with Freundlich rather than Temkin and Langmuir isotherm models. The thermodynamic studies reflected the endothermic nature and the exothermic nature for the adsorption by K/CNTs and K/starch nanocomposites, respectively. Natural ground water contaminated by 0.4 mg/L Fe and 0.5 mg/L Mn was treated at the optimum conditions of pH 6 and 120 min contact time. Under these conditions, 92.5 and 72.5% Fe removal efficiencies were achieved using 20 mg of K/CNTs and K/starch nanocomposites, respectively. Also, K/CNTs nanocomposite shows higher efficiency in the removal of Mn ions as compared to K/starch nanocomposite.