Removal of Solophenyl Red 3BL Dye from Textile Effluents by Adsorption Using a Natural Adsorbent Oxalis pes-caprae L.

The aim of the present study was to assess the adsorption potential of a natural adsorbent Oxalis pes-caprae L. for the removal of azo-dye solophenyl red 3BL (SR 3BL) from textile effluents. The adsorbent was characterized by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The effect of various parameters on the efficiency of the adsorption was studied. The optimum was found with the contact time of 35 minutes, pH of 6, and temperature of 25 °C. The equilibrium experimental data were fitted with the Langmuir, Freundlich, and Temkin models. Experimental data were well described with the Langmuir isotherm indicating monolayer adsorption. Pseudo-first-order, pseudo-second-order, and Elovich kinetic models were used to evaluate the adsorption kinetics. The adsorption kinetics was found to follow closely the pseudo-first-order kinetic model. Thermodynamics studies revealed that the adsorption process was spontaneous and exothermic. This work is licensed under a Creative Commons Attribution 4.0 International License

Adsorption of zinc and cadmium from aqueous solutions using bentonite/polypyrrole composite

In this study, removal of zinc (Zn2+) and cadmium (Cd2+) from aqueous solutions is investigated using bentonite/polypyrrole (B-Ppy) composite. The effect of pH, initial ion concentration and time were determined using batch adsorption technique. Maximum adsorption was recorded at a pH of 5 and equilibrium sorption was achieved within 60 minutes of the process. Equilibrium isotherm models applied showed the Langmuir and Freundlich isotherms model with the best regression coefficient R2 The Langmuir isotherm constant (b) and the Freundlich constant (n) indicated a high affinity of B-Ppy composite for zinc (II) and cadmium (II) ions. The surface morphology, the thermal and optical properties of the composite were studied with scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and UV-vis spectroscopy, respectively. The results show that the addition of the bentonite improves the thermal stability of polypyrrole (Ppy) which is due to the interfacial interaction between the Ppy and the bentonite. The experimental results indicated the potential of B-Ppy composite as a low-cost adsorbent for zinc and cadmium removal from aqueous solution

Sustainable Extraction, Chemical Profile, Cytotoxic and Antileishmanial Activities In-Vitro of Some <i>Citrus</i> Species Leaves Essential Oils

Anti-leishmanial drugs extracted from natural sources have not been sufficiently explored in the literature. Until now, leishmaniasis treatments have been limited to synthetic and expensive drugs. This study investigated, for the first time, the anti-leishmanial efficacy of essential oils (EOs) from the leaves of Citrus species (C. sinensis, C. limon, and C. clementina). Essential oils were extracted from three species by solvent free microwave extraction (SFME); in addition, lemon oil was also isolated by hydro-distillation (HD). These were investigated using gas chromatography coupled with mass spectrometry (GC–MS) and evaluated against Leishmania species, namely Leishmania major and Leishmania infantum, using a mitochondrial tetrazolium test (MTT) assay. The chemical compositions of Citrus limon EOs obtained by HD and SFME showed some differences. The identified peaks of C. limon (SFME) represented 93.96%, where linalool was the major peak (44.21%), followed by sabinene (14.22%) and ocimene (6.09%). While the hydro-distilled oil of C. limon contained geranial (30.08%), limonene (27.09%), and neral (22.87%) in the identified peaks (96.67%). The identified components of C. clementina leaves oil (68.54%) showed twenty-six compounds, where the predominant compound was geranial (42.40%), followed by neral (26.79%) and limonene (14.48%). However, 89.82% C. sinensis oil was identified, where the major peaks were for neral (27.52%), linalool (25.83%), and geranial (23.44%). HD oil of lemon showed the highest activity against L. major, with moderate toxicity on murine macrophage (RAW 264.7) cells, and possessed the best selectivity index on both Leishmanial species (SI: 3.68; 6.38), followed by C. clementina oil and C. limon using SFME (0.9 ± 0.29, 1.03 ± 0.27, and 1.13 ± 0.3), respectively. C. clementina oil induced the greatest activity on Leishmania infantum, followed by HD lemon and SFME lemon oils (0.32 ± 0.18, 0.52 ± 0.15, and 0.57 ± 0.09, respectively) when compared to Amphotericin B (0.80 ± 0.18 and 0.23 ± 0.13) as a positive control, on both species, respectively. Our study suggests a potent anti-leishmanial activity of lemon oil (HD) on L. major, followed by C. clementina. With the same potency on L. infantum shown by C. clementina oil, followed by HD lemon oil. This effect could be attributed to the major compounds of limonene, citral, and neral, as well as the synergistic effect of other different compounds. These observations could be a starting point for the building of new anti-leishmanial drugs from natural origins, and which combine different EOs containing Citrus cultivars