Hassan Ouallal

The present study evaluates the effectiveness of raw Goulmima clay from Morocco in removing malachite green from aqueous media. Experiments were carried out to examine the impact of different factors on the adsorption process, including thermodynamic, kinetic, and adsorption isotherm analyses. The findings indicate that the mass of adsorbent, initial solute concentration, stirring speed, temperature, and contact time affect how well malachite green adsorbs onto the clay. Increasing adsorbent of mass from 10 to 50 mg leads to a decrease in the adsorbed quantity from 60 to 13 mg/g. Conversely, raising the initial malachite green concentration from 5.10-6 to 10-4 M increased the quantity adsorbed from 2.60 to 39.86 mg/g within five minutes. Adsorption equilibrium was reached within 40 minutes. Both temperature and stirring speed had a slight positive effect, indicating the endothermicity of the process, as supported by the thermodynamic results. The isothermal and kinetic model evaluations indicated a strong fit between the experimental data and the non-linear forms of the Langmuir model and the pseudo-second-order model. Comparative analysis with other mineral materials shows that raw Goulmima clay demonstrates superior adsorption efficiency for malachite green. This positions it as a more effective and cost-efficient adsorbent than many other commonly used mineral materials. These findings suggest that the studied clay holds significant promise for practical applications in cleaning water loaded with malachite green dye.

This work investigates the potential of Natural Moroccan Clay (NMC) sourced from the Draa-Tafilalet region for removing malachite green from aqueous media through adsorption. X-ray diffraction (XRD) and scanning electron microscopy combined with energy-dispersive X-ray microanalysis (SEM/EDX) were used to characterize the clay. Malachite green (MG) was subjected to batch adsorption experiments, and a kinetic study was carried out at three concentrations (5, 50, and 100 mg/L). The results showed that adsorption is typically fast for all three concentrations and that the adsorbed amount rises with time and dye concentration. Equilibrium is reached within just 40 minutes. The kinetics adsorption at varying MG concentrations were modeled using non-linear and linear forms of pseudo-first order and pseudo-second order and with intraparticle diffusion models. The non-linear form of the pseudo-second-order model was found to be best suited to describing this adsorption process. The isotherm was studied using two models: Freundlich and Langmuir. According to the error functions analysis, the Langmuir model is well suited for equilibrium data fitting. Investigated clay attained an adsorption capacity of 214 mg/g. SEM/EDX characterization of NMC before and after adsorption confirms the malachite green adsorption on the NMC surface. These results illustrate the effectiveness of the investigated clay as a cost-effective adsorbent.

This study focuses on the removal of phenol from aqueous media using Agouraï clay (Fes-Meknes-Morocco region) and Geulmima clay (Draa Tafilalet region). The characterization of the clay by Fourier Transform Infrared (FTIR) Spectroscopy, X-ray diffraction (XRD), N2 adsorption (BET), Scanning Electron Microscopy (SEM), and Thermogravimetric and differential thermal analysis (DTA/GTA) indicates that it is mainly composed of quartz, kaolinite, and illite. The results showed that raw Clay Agourai (RCA) and raw Clay Geulmima (RCG) adsorbed phenol very quickly and reached equilibrium after 30 min. Thermodynamic parameters reveal the physical nature of the adsorption, the spontaneity, and the sequence of the process. However, the structure and structural characterization of the solid before and after phenol adsorption indicated that the mechanism of the reaction was electrostatic and that hydrogen bonding played an important role in RCG, while kinetic modeling showed the pseudo-second-order model dynamics. The physics-statistics modeling was employed for describing the isotherm adsorption for both systems. It was found that the monolayer model with two different energy sites best describes adsorption irrespective of the system. The model indicates that the receptor density of each clay direct influences the adsorption capacity, demonstrating that the composition of the clay is the main source of the difference. Thermodynamic simulations have shown that the adsorption of phenol is spontaneous and endothermic, irrespective of the system. In addition, thermodynamic simulations show that the RCG could be adsorbed even further since the equilibrium was not achieved for any thermodynamic variable. The strength of this study lies in the determination of the adsorption mechanism of phenol on clay materials and the optimum values of temperature and pH.

The region of Meknes suffers from a significant delay in the water sector, including sewage treatment. The Urban waste water in the region originates from various activities; households, industry, agriculture and hospital. These waters are released in to nature without any treatment, which constitutes a serious risk for the environment. The objective of this research is to characterize the physicochemical and bacteriological pollution of the three sewage collectors of the Meknes region (Aïn Choubbik, Oued Ouislane and Aïn Taoujdate). Indeed, the pollution parameters; biological and chemical oxygen demand are abnormally high, which indicates clearly that waste waters is rich of reducing or oxidizing organic materials. Ammonium, nitrogen, phosphorus and heavy metals concentrations exceed the limit values. So these waters are classified as bad or very bad quality. On the one hand, the presence of a large bacterial load indicates fecal contamination. The total coliform, fecal coliform and fecal streptococci levels are high exceeding exceed the values specified the WHO guidelines and the Moroccan standards. This situation is likely to cause serious and irreparable damage to the environment groundwater. To counter this, make the necessary investment in sewage treatment and other remedial measures is key to preventing pollution and its spread.