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This study involves the adsorption of Crystal Violet (CV) dye adsorbed from solution on the pyrophyllite's surface. The batch technique was used under a variety of conditions to produce quantitative adsorption, namely amount of adsorbent, dye concentration, contact time, pH solution and temperature. The maximum adsorption capacity of Crystal Violet on pyrophyllite was 9.58 mg/g for 10 mg/L of CV concentration, pH = 6.8 at a temperature 20°C and 1 g/L of adsorbent. This study of adsorption kinetics was carried out within framework of three models: intraparticle diffusion, pseudo-first order and pseudo-second order. The experimental isotherm data were analyzed using Langmuir and Freundlich models. Different thermodynamic parameters have shown spontaneous reaction with endothermic nature (The estimated value for DG was À7.64 kJ/mol at 293 K). Various techniques for characterizing the adsorbent were applied including X-ray diffraction (XRD), X-ray fluorescence spectroscopy (XRF), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) coupled by energy dispersive X-ray spectroscopy (EDX). In addition, the regenerated adsorbents technique was reused several times; this demonstrated an economical aspect of using pyrophyllite which underlines the re-use importance considering the material capacity to regenerate.

The end of the year 2019 was marked by the introduction of a third highly pathogenic coronavirus, after SARS-CoV (2003) and MERS-CoV (2012), in the human population which was officially declared a global pandemic by the World Health Organization (WHO) on March 11, 2020. Indeed, the pandemic of COVID-19 (Coronavirus Disease 19) has evolved at an unprecedented rate: after its emergence in Wuhan, the capital of the province of Hubei of the People's Republic of China, in December 2019, the total number of confirmed cases did not cease growing very quickly in the world. In this manuscript, we have provided an overview of the impact of COVID-19 on health, and we have proposed different nutrients suitable for infected patients to boost their immune systems. On the other hand, we have described the advantages and disadvantages of COVID-19 on the environment including the quality of water, air, waste management, and energy consumption, as well as the impact of this pandemic on human psychology, the educational system, and the global economy. In addition, we have tried to come up with some solutions to counter the negative repercussions of the pandemic.

The present study aimed to determine the chemical composition and the synergistic effect of three plants’ essential oils (EOs), Eucalyptus camaldulensis (ECEO), Mentha pulegium (MPEO), and Rosmarinus officinalis (ROEO), against three bacterial strains, Proteus mirabilis, Klebsiella pneumoniae, and Staphylococcus aureus, in order to increase the antimicrobial effectiveness by the use of a low dose of essential oils, consequently decreasing the toxicity and negative impact. For this reason, an augmented simplex-centroid mixture design was used to build polynomial models in order to highlight the synergy between the essential oils against bacterial strains. Antimicrobial effect screening was performed by the disc diffusion method and the minimal inhibitory concentrations (MIC) were also studied. The gas chromatography/mass spectrometry (GC-MS) results show the richness of these essential oils by terpenic compounds, especially 1,8-Cineole and P-Cymene for ECEO, Pulegone for MPEO, and α -Pinene and Camphene for ROEO. Moreover, a significant antibacterial effect has been demonstrated and the best values were revealed by MPEO and ECEO against P. mirabilis and K. pneumoniae, with inhibition zones (IZ) of 25 and 20 mm, respectively, and an MIC of 0.0391% (v:v) against K. pneumoniae. The optimal mixtures showed a synergistic effect of essential oils, and the lowest minimal inhibitory concentrations of the mixtures (MICm) were in the order of 29.38% of MPEO, 45.37% of ECEO, and 25.25% of ROEO against P. mirabilis and in the order of 60.61% of MPEO and 39.39% of ROEO against K. pneumoniae. These results indicate the antibacterial efficacy of the three essential oils combined and suggest their importance in the treatment of urinary tract infections caused by resistant bacterial strains.

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