Characterization of the reverse osmosis membrane fouled by Oum Errabia river water of Khenifra city, Morocco

The Khenifra desalination plant is designed to produce 36,290 m3/d of drinking water by 2030. Since the start-up of this plant in 2013, several problems have been encountered in the reverse osmosis unit due to membrane fouling. Clogging is a major issue related to the interaction between feed water quality and the pre-treatment process. Membrane autopsy, monitoring of seasonal variations in raw water and surveillance of operating parameters are carried out. The results obtained show that feed water is subject to large seasonal variations in terms of temperature (10 - 25 °C), conductivity (1395 - 2500 µS.cm-1) and Silt Density Index (SDI) (< 3) in 2017 using microfiltration, which influences the fouling of the membrane. Membrane autopsy by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS) and X-ray Diffraction (XRD), shows the formation of large cracks on the surface of the membrane and that the fouling layer is mainly composed of: CaCO3 (38.70 %), Al2O3 (17.42 %), Ba(SO4)2 (15.23 %), MgCl2 (15.02 %) and SiO2 (13.64%)

Bioadsorption of CI Reactive Blue 203 dye by duckweed Lemna gibba’s powder

: Many contaminants, especially dyes used to manufacture paint, textiles, and other products, are released into the aquatic environment as a result of human population increase and industrialization. In this study, it was chosen to develop a plant biomaterial compatible with the demand of the world market in cost terms, and to focus on the reuse of powder duckweed Lemna gibba as a new effective material for the removal of dyes in particular, considering this plant's capacity for purification even in the waste state after assisting a lagoon plant achieve phytoremediation. After analyzing the effects of pH, contact time, adsorbate concentration, and adsorbent dosage on the dye (CI Reactive Blue 203)'s adsorption process on the plant powder Lemna gibba, it was determined that the adsorption kinetics follows the pseudo first order model and the adsorption isotherm is best described by the Langmuir model, and that the percentage of dye removal reaches 90% at pH 3 of the solution, and the adsorption capacity reaches its maximum of 96% at only 0.5g of the powder and 25 mL of the solution. As a result, this study recommends using powder Lemna gibba plant as an alternative for activated carbon in adsorption

Study of Reactive blue 203 removal by TiO2-P25 adsorption combined with photocatalysis for its degradation

The treatment of wastewater containing textile dyes is a major environmental challenge due to the complexity of the effluents and the diversity of chemical compounds involved. In this study, we explored adsorption and photocatalysis to improve the purification efficiency of these waters. Adsorption on TiO2-P25 proved particularly effective in removing RB203 dye, reaching equilibrium in around 180 minutes, with optimum conditions A 25mL volume containing of 40 mg/L dye, 0.125 g TiO2-P25, pH 3, stirring speed 300 rpm and temperature 25°C. Photocatalysis using TiO2-P25 has shown promising results under solar irradiation, particularly with TiO2-P25 recycling techniques to reduce costs and improve durability. This study proposes effective solutions for the treatment of wastewater containing textile dyes, with specific recommendations for their practical application in industrial facilities, and future prospects include the optimization of treatment conditions and the integration of these processes into wider systems for sustainable environmental management. Keywords: TiO2; RB203; Solar photocatalysis; Photodegradation; Adsorption, Water treatment

Pt-Sn/C as a possible methanol-tolerant cathode catalyst for DMFC

An effective method was developed for preparing highly dispersed nano-sized Pt–Sn/C electrocatalyst synthesised by a modified polyol reduction method. From XRD patterns, the Pt–Sn/C peaks shifted slightly to lower 2θ angles when compared with commercial Pt/C catalyst, suggesting that Sn formed alloy with Pt. Based on HR-TEM images, the Pt–Sn/C nanoparticles showed small particle sizes and well dispersed onto the carbon support with a narrow particle distribution. The methanol oxidation reaction on the as-prepared Pt–Sn/C catalyst appeared at lower currents (+7.08 mA at +480 mV vs. Ag/AgCl) compared to the commercial Pt/C (+8.25 mA at +480 mV vs. Ag/AgCl) suggesting that the Pt–Sn/C catalyst has ‘methanol tolerance capabilities’. Pt–Sn/C HA Slurry pH3 catalysts showed better activity towards the oxygen-reduction reaction (ORR) than commercial Pt/C which could be attributed to smaller particle sizes. In our study, the Pt–Sn/C catalyst appears to be a promising methanol-tolerant catalyst with activity towards the ORR in the DMFC.Web of Scienc

Growth and characterization of electrodeposited Na0.45VOPO4, 1.58H2O materials

International audienceThe paper reports on a new and original way to prepare sodium vanadophosphate by using the electrochemical oxidation of vanadyl ions in H3PO4 solution to produce a deposit onto the electrode. Such a way insured an intimate mixing of the component elements in the solution allowing finer particles and high purity materials to be produced by rapid homogenous nucleation. The experimental conditions to obtain a pure phase are described in the paper. The main determining parameter is the solution pH which had to be adjusted at 1.9 or 2.0 with NaOH. A mixture of sodium vanadophosphate and V2O5, 0.5H2O was obtained for higher pH= 2.2. A series of experiments including an X-ray diffraction study, thermogravimetric analysis, transmission electron microscopy and infrared spectroscopy investigation helped in determining the exact chemical formula of the obtained phase, i.e. Na0.45VOPO4, 1.58H2O. The phase exhibits an orthorhombic structure with a = 8.85 Å, b = 9.01 Å and c = 13.02 Å

Mineralization of herbicides imazapyr and imazaquin in aqueous medium by, Fenton, photo-Fenton and électro-Fenton processes.

International audienc

Mineralization of herbicides imazapyr and imazaquin in aqueous medium by, Fenton, photo-Fenton and électro-Fenton processes.

International audienc

The effect of Cu and Cu-humic acids on the adsorption of imazethapyr herbicide by montmorillonite clay

Adsorption of imazethapyr, an imidazolinone herbicide, was measured from dilute suspensions onto montmorillonite clay and complexes of montmorillonite with Cu and humic acid. Adsorption of imazethapyr was found to be greater for the Cu-montmorillonite and Cu-humic acid-montmorillonite complexes than by montmorillonite alone. Isotherm shape was similar for all supports studied. Adsorption of imazethapyr varied with pH for montmorillonite and for Cu-humic acid-montmorillonite complex. The pH had no apparent effect on imazethapyr adsorption to the Cu-montmorillonite complex. This might be due to imazethapyr retention at high pH by Cu ions linked to the clay. Imazethapyr adsorption kinetics was faster for Cu-montmorillonite (15 min) and Cu-humic acid-montmorillonite (30 min) than for montmorillonite (240 min). The copper-humic acid complexes with montmorillonite might be used to detoxify water contaminated with imazethapyr