Ahmed Addou

Methylene blue and iodine adsorption onto an activated desert plant.

Although frequently less toxic than many colorless effluents, colored effluents are generally considered by the public as an indicator of pollution. The present investigation aimed at identifying the effectiveness of a local desert plant characteristic of Southwest Algeria and known as Salsolavermiculata, which was pyrolyzed and treated chemically with a 50% zinc chloride solution, to remove methylene blue and iodine. The natural plant adsorption capacities were respectively 23mg/g and 272mg/g for methylene blue and iodine. Corresponding results for the pyrolyzed plant uptakes were 53mg/g and 951mg/g, while those for the pyrolyzed plant, chemically treated and activated at 650 degrees C, were 130mg/g and 1178mg/g, respectively. In comparison, the standard Merck activated carbon capacities were 200mg/g for methylene blue and 950mg/g for iodine. Consequently, this low-cost local plant may also prove useful for the removal of large organic molecules as well as potential inorganic contaminants.

Density and Rotational Temperature Measurements of the OH° and NO° Radicals Produced by a Gliding Arc in Humid Air

The predominant reactive species of a gliding arc in humid air, 50% relative humidity (50% RH), are identified from emission spectroscopy measurements to understand and explain the glidarc plasma interaction with aqueous solutions. The rotational temperatures of the main particles (i.e., the OH° and NO° radicals) are derived from comparing experimental and synthetic spectra at various locations in the plasma stream with different airflow rates. The temperatures decrease rather moderately downstream from the starting section of the arc (the neck) and they rather steeply increase with increasing the mass flow rate. Density measurements are also performed for the same experimental conditions to determine their evolution in the non-equilibrium zone. Although they are quasi-constant along the plasma jet axis, the OH° density is much higher than the NO° one. The chemical processes, which may lead to a constant regeneration of these prevailing reactive particles in a humid air gliding arc plasma, are also discussed. The complex composition of the plasma gas makes other chemical processes fairly possible, which may result in abundant species depending on the compound proportions.

Enhancement of the bleaching and degradation of textile wastewaters by Gliding arc discharge plasma in the presence of TiO2 catalyst.

The degradation of two polluted textile wastewaters from SOITEX (silk and textile) industry using the plasma-catalytic process, has been studied by non-thermal Gliding arc technique coupled to Degussa P25 titanium dioxide (TiO(2)) as photo-catalyst. Experiments were carried out to optimise the amount of phtoto-catalyst. The results showed that maximum degradation was attained for 3 g L(-1) TiO(2) concentration. For wastewater (1) degradation was 95% at the end of 60 min of treatment time. The same wastewater was completely decolourised after only 30min of plasma-catalytic treatment time. In parallel, the biodegradability was significantly enhanced through 20 min of exposure to the plasmagenous source for both wastewater samples. Turbidity of wastewater (1) and wastewater (2) decreased with rate constants of 0.015 and 0.017m in(-1), respectively. The TiO(2)-mediated Gliding Arc discharge (GAD(TiO(2)) showed potential application for the treatment of liquid wastes, resulting in the mineralization of the wastewater samples confirmed by chloride, sulphate and phosphate ions formation. In both cases of GAD treatments, with and without photo-catalyst, the plasmagenous process proves efficient in the field of wastewaters degradation.

Municipal solid waste in Mostaganem city (Western Algeria).

The management of municipal solid waste (MSW) and valorisation is based on the understanding of MSW composition by its categories and physicochemical characteristics. In this study, we characterize and determine physicochemical parameters (density, fire loss, electric conductivity, average pH, moisture level, lower calorific value (LCV), total and organic carbon, and nitrogen) in order to establish MSW valorisation models for Mostaganem city (located in Western Algeria). The results show that organic matter represents 64.6% of waste, followed by paper-cardboard 15.9%, plastic 10.5%, glass 2.8%, textile 2.3%, metals 1.9%, and diverse materials 2%. These statistics are similar to results from developing countries, especially if organic matter, paper and plastic are taken into account, but differ from developed countries. This reflects the difference in lifestyle and consumption behaviour between the two communities. The parameters used to determine the possible valorisation model had the following average values: fire loss (63%); ash (37%); pH (6.1); electric conductivity (2.39 ms cm(-1)); total carbon (29.5%); nitrogen (1.5%); LCV (1028.6 kcal/kg), density (0.36), C/N (19.7) and moisture level (58.9%). The study shows that 31.1% of paper-cardboard, plastic, glass and metal wastes are recyclable. Incinerating MSW, with energy recovery, was a poor option because of the weak LCV (1028.6 kcal/kg). However, MSW produced a good methane yield of up to 1852.4 equivalent tons of oil per year. The agricultural benefits, C/N ratio values, levels of moisture and pH and the Tanner diagram all supported compost production.

Healthcare waste management in Algeria and Mostaganem department.

Algeria as other developing countries faces an array of challenges for healthcare waste management. The management of healthcare waste is of major importance due to its public health risks and potential environmental hazards. Many efforts have been made by the government authorities in order to better manage the waste from healthcare facilities. However most healthcare facilities do not comply with the principles stated in Algerian legislation. A data study was made on 95 hospitals across the country, and the three health sectors of Mostaganem department (Mostaganem, Ain Tédles, and Sidi Ali) were surveyed. The yearly production of infectious healthcare waste in this Algerian department is estimated at 92 tons, which is 1.38% of the national waste production. This represents an average of 0.15 kg/bed/day, which is lower than the national value of 0.72 kg/bed/day. The total healthcare waste by sector ranges from 0.7 to 1.22 kg/bed/day, and healthcare waste comprises 16% of total waste, which is equal to the national percentage.

Post-discharge plasma-chemical oxidation of Iron(II) complexes

The plasmachemical properties of an electric discharge in humid air are considered by examining the oxidation of Fe(II) to Fe(III) aquo-ions in a solution exposed to the discharge. The reaction product is characterised and quantified by means of the thiocyanate complex FeSCN2+. The reaction mechanism shows two distinct steps: a rapid step directly depending on the treatment time and a slow post-discharge step, which are both ascribed to species formed in the discharge (i.e., respectively to OH radical and to hydrogen peroxide or nitrate ions). These concerned species are able to react either at the liquid surface (OH) or to diffuse into the solution and react as solutes. Experimental arguments in favour of zero and first order reaction steps are given. A particular reactor design involving a multibladed electrode is tested at the juncture and its use considered for further industrial applications.

The Adsorption of Pentachlorophenol from Aqueous Solutions onto Exchanged Al-MCM-41 Materials

The ability of a mesoporous molecular sieve to adsorb chlorinated phenols was studied experimentally. Thus, the adsorption isotherms of pentachlorophenol (PCP) from aqueous solutions were measured on (M)Al-MCM-41 (M = Na+, K+, Cu2+, Cr3+) at intervals of 10 K between 303 K and 323 K. The experimental isotherms obtained were of the S-type in terms of the classification of Giles and co-workers. The best fit of the adsorption isotherm data was obtained using the Freundlich model. The adsorption affinity of PCP increased in the order (K)Al-MCM-41 < (Cr)Al-MCM-41 < (Na)Al-MCM-41 < (Cu)Al-MCM-41. At the same temperature, the adsorption of PCP on (Cu)Al-MCM-41 was more pronounced compared to its adsorption on alumina-pillared montmorillonite and mesoporous alumina aluminium phosphates. Analysis of the isosteric curves showed that (Cu)Al-MCM-41 and (Na)Al-MCM-41 presented a heterogeneous profile. In contrast, (K)Al-MCM-41 and (Cr)Al-MCM-41 did not exhibit energetic heterogeneity throughout the entire range of coverage.

Plasmacatalytic removal of lead acetate assisted by precipitation.

The Gliding Arc Discharge (GAD) is an efficient non-thermal plasma technique able to degrade organic compounds dispersed in water at atmospheric pressure. The degradation of the organometallic lead acetate (PbAc) in aqueous solution was performed by two distinct plasmageneous processes: GAD and GAD/TiO2. The global oxidation of the organic matter was followed by Chemical Oxygen Demand (COD) and the mineralization was determined by the Total Organic Carbon (TOC). The Pb(2+) ions released during the degradation process were measured by Atomic Absorption Spectroscopy (AAS). For 2h of GAD treatment, the degradation rate of PbAc (10mM) reached 83% and for the same duration of GAD/TiO2 process ([TiO2]=1gL(-1)), it reached 93%. The release of Pb(2+) ions in the solution was respectively of 95% and 57% for GAD and GAD/TiO2 processes. The released Pb(2+) ions were removed by precipitation process in a basic medium at pH=11.1. A reaction mechanism was proposed to explain the PbAc molecule degradation and the Pb(2+) elimination.

Antimicrobial Activity of 22 Plants Used in Urolithiasis Medicine in Western Algeria

Objective Our investigation is about the determination of the antibacterial efficiency of 22 medicinal plants on the four most frequent bacteria in urinary infections. These infections are responsible for more than 15% of urinary stones formation.

Non-Thermal Plasma degradation of wastewater in presence of titanium oxide by gliding arc discharge

Degradation of polluted plastic and rubber wastewater using the plasmachemical and plasmacatalytic process has been studied by non-thermal gliding arc technique. The gaseous species formed in the discharge, and especially the °OH radicals, induced strong oxidising effects in the target solution. The treatment with TiO2 photo-catalyst led to a degradation of 80% in 60 min, a decrease of turbidity of 92% and enabled the wastewater to become biodegradable in less than 30 min. In both cases of treatment with and without catalyst, the plasmageneous process appears to give once more satisfactory results in the field of wastewaters degradation.