This article presents a study of cadmium removal from nitrate medium using adsorption in calcined mesoporous silica (MCM-C), mesoporous silica doped (MCM_DIOPA), and calcined and impregnated mesoporous silica (MCM@DIOPA), with diisooctylphosphinic acid (DIOPA). The sorbents were synthesized via a sol–gel method. Several characterization techniques, such as XRD, FTIR spectroscopy, N2 sorption and elemental analysis, have been used to determine the main structural, textural, and chemical properties of prepared sorbents. Batch adsorption and kinetics tests were carried out, where the influence of pH and contact time of the sorbents and their role in cation removal were studied. Experimental results show poor sorption efficiencies with MCM-C and MCM_DIOPA at pH 5.85. At the same pH, better cadmium extraction was attained by MCM@DIOPA and was achieved within 30 min. The pseudo-second-order model is the most appropriate model to describe the elimination mechanism of Cd(II) ions. The Langmuir equation was used to model the sorption isotherm and the maximum sorption capacity of Cd(II) is 22.16 mg/g (200 mmol/kg). The complex type of the probable extracted species isCdL2-HL.

Removal of heavy metals from wastewater is mandatory in order to avoid water pollution of natural reservoirs. In the present study, layered double hydroxide (LDH) materials were evaluated for removal of zinc from aqueous solutions. Materials thus prepared were impregnated with cyanex 272 using the dry method. These materials were characterized through X-ray diffraction (XRD), Fourier transform infrared (FTIR), and thermal analysis. Batch shaking adsorption experiments were performed in order to examine contact time and extraction capacity in the removal process. Results showed that the equilibrium time of Zn (II) extraction is about 4 h for Mg2Al-CO3 and Mg2Al-CO3-cyanex 272, 6 h for Zn2Al-CO3, and 24 h for Zn2Al-CO3-cyanex 272. The experimental equilibrium data were tested for Langmuir, and Freundlich isotherm models. Correlation coefficients indicate that experimental results are in a good agreement with Langmuir’s model for zinc ions. Pseudo-first, second-order, Elovich, and intraparticular kinetic models were used to describe kinetic data. It was determined that removal of Zn2+ was well-fitted by a second-order reaction kinetic. A maximum capacity of 280 mg/g was obtained by Zn2Al-CO3-cyanex 272.

Mesoporous silica impregnate with Cyanex 272 (bis/2,4,4-trimethylpentyl/phosphinic acid) extractant was immobilized into an alginate matrix to obtain a composite sorbent easy to use and applicable in fixed-bed column continuous systems. The sorption efficiency of this material was tested for the recovery of Eu(III) ions from aqueous solutions in batch and continuous mode. The competition among rare earths ions (europium, lanthanum, and lutetium) and among rare earths and calcium or sodium ions was investigated. High calcium concentrations strongly reduce the sorption capacity of the alginate matrix that composes the hybrid material and the Cyanex 272 impregnated into silica powder improves the rare earths' sorption performance in this calcium charged media. The experimental breakthrough curves obtained were satisfactory fitted by Thomas model.

Boron removal was evaluated in the present work by using calcium alginate beads (CA) and a novel composite based on alginate–alumina (CAAl) as sorbents in a batch system. The effects of different parameters such as pH, temperature, contact time, and composition of alginate (at different concentrations of guluronic and mannuronic acids) on boron sorption were investigated. The results confirm that calcium alginate beads (CA) exhibited a better adsorption capacity in a slightly basic medium, and the composite alginate–alumina (CAAl) exhibited improved boron removal at neutral pH. Sorption isotherm studies were performed and the Langmuir isotherm model was found to fit the experimental data. The maximum sorption capacities were 4.5 mmol g−1 and 5.2 mmol g−1, using CA and CAAl, respectively. Thermodynamic parameters such as change in free energy (ΔG0), enthalpy (ΔH0), and entropy (ΔS0) were also determined. The pseudo-first-order and pseudo-second-order rate equations (PFORE and PSORE, respectively) were tested to fit the kinetic data; the experimental results can be better described with PSORE. The regeneration of the loaded sorbents was demonstrated by using dilute HCl solution (distilled water at pH 3) as eluent for metal recovery.

This work aims to the enhancement of low cost MCM-41 adsorption capacity of copper and iron ions separately and as a mixture from solution and subsequently their use in antibacterial and antifungal activities. MCM-41 mesoporous were synthesized from used spent glass as source of silicon and aluminum. The hybrid MCM-41 mesoporous were obtained by impregnation of 8-hydroxyquinoline 5-sulfonic acid on the MCM-41 pores under different mass ratios (5, 10, 15, 20 and 25%). The hybrid solids were characterized by x-ray diffraction (XRD), and the presence of 8-hydroxyquinoline 5-sulfonic acid in hybrid MCM-41 is verified by thermogravimetric analysis and infrared spectroscopy. The effect of contact time, initial pH of a solution, heavy metal concentrations and 8-hydroxyquinoline 5-sulfonic acid content on the adsorption efficiency were investigated. Pseudo-first/second order isotherms are applied to determine the efficiency of hybrid solid. The experimental data fitted well with the pseudo-second order model for Cu2+ and Fe2+ adsorption. Maximum yields for Cu2+ and Fe2+ were 94% and 95% respectively. However, the extraction yield for both ion metals seems to be increase to reach 98.24% and 95.10% for iron and copper respectively when both solutions are mixed together. The hybrid MCM-41 with higher extraction yield for both metal ions and for mixture are applied as antibacterial inhibitors against Gram-negative (E. coli ATCC 25922, P. aeruginosa ATCC 27853,), Gram-positive (S. aureus1 ATCC 25923, S. aureus2 ATCC 43300) bacteria and also as antifungal against Candida albicans ATCC 10231. The obtained results of the application of hybrid MCM-sox Cu, Fe and Cu/Fe as antibacterial and antifungal inhibitors seem to be very promising material in the adsorption and antimicrobial fields.

This work reports the synthesis of mesoporous silica impregnated by an acidic organophosphinic ligand (Cyanex 272) for the extraction of rare earth elements (REE). The prepared solid was characterized by X-ray diffraction (XRD), and N-2 sorption at 77 K. The effect of pH, ligand loading, time and initial concentration on REE extraction were studied. Selectivity between light lanthanides (La), medium (Eu) and heavy lanthanides (Lu) followed the usual order Lu > Eu > La. The stoichiometry of the different species formed inside the porosity according to the conditions of the extraction (lanthanide nature and concentration; ligand loading) is proposed. The phosphinic ligand Cyanex 272 showed encouraging complexing properties in the porosity of the silica for its use in extraction and separation of rare earth metals.

In this paper, the authors treat the impact of peat amendment on sorption and leaching of fungicides penconazole and flusilazole in two Algerian topsoil samples (Misserghine and Es-Senia). The batch equilibration technique was applied for adsorption experiments, and leaching was tested through soil column simulated experiments under laboratory conditions. Adsorption data fitted well to the Freundlich and linear models, showing the higher adsorption capacity of the Es-Senia soil for both fungicides, the order of sorption being flusilazole > penconazole. Organic amendments increased the adsorption of both fungicides especially for the soil with the lower organic matter (OM) content, obtaining a good correlation of this parameter with K f, thus implying that OM is the principal soil parameter governing fungicides adsorption. Results of soil column experiments indicated that peat amendment decreased leaching of both pesticides in the soils studied. So, the use of organic addition might be an effective management practice for controlling potential pollution of penconazole and/or flusilazole to the environment.

This paper deals with the potential use of hybrid magadiite composite as an alternative adsorbent for the removal of copper ions. Na-magadiite was synthesized by the hydrothermal method. The hybrid magadiite was prepared by using pyrazolone as an organic ligand via dry impregnation technique from Na-magadiite. The hybrid magadiite composite is used in the removal of copper ions in sulphate media. The presence of an organic molecule in hybride magadiite is verified by thermogravimetric analysis and infrared spectroscopy. The X-ray diffraction pattern illustrates the intercalation of the organic ligand into Na-magadiite interlayers and the preservation of the structure after intercalation. The scanning electron micrograph images of modified Na-magadiite show the expansion of the basal spacing resulted in a breakup of the spherical nodules and the concomitant parallel arrangement of the platelets. In batch experiments, the influence of reaction time, kinetics, pH and the initial concentration of copper(II) were investigated. In the case of modified Na-magadiite, the kinetic model of extraction adapted is pseudo-second order. The metallic cation was extracted at a very low pH 1.9, and the capacity obtained is 330 mmol/kg, the complex formed is of the CuL 2 type.

The sorption of cadmium from nitrate medium at room temperature was carried out using solid phase magadiite and magadiite impregnated with Cyanex 272 [bis(2,4,4-trimethylpentyl)phosphinic acid]. The sorbent materials have been characterized by X-ray diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FTIR), scanning electron microscopy-energy dispersive X-ray analyses (SEM-EDX) and thermogravimetric analysis (TGA/DTG). The UV-vis spectrophotometry technique was used to determine the amount of Cyanex-272 inserted into the solid support. Various parameters such as pH of the aqueous solution, initial Cd(II) concentration and equilibrium time were studied. The sorption data fitted the Sips sorption equation, and the sorption kinetics follows the model of the pseudo-second order. The maximum sorption capacity of Cd(II) was found to be 64.06 mg g(-1 )and 49.45 mg g(-1) (i.e., 0.57 and 0.44 mmol g(-1)) from magadiite and magadiite-Cyanex 272, respectively. The elution of the materials was performed with 0.1 M HNO3 solution, and 80% of the initial sorbed cadmium was recovered.

Impregnated homoionic raw Algerian bentonite (HB) with high basal spacing was prepared to remove a copper (Cu2+) and zinc (Zn2+) from 0.33M (Na+, H+)SO42− sulphate medium in aqueous solutions. The impregnated solid was characterized by X-ray diffraction (XRD), Fourier- Transform Infrared (FTIR) and Ultra-violet (UV). The effect of contact time, initial pH of a solution, heavy metal concentration and ligand concentration on the adsorption efficiency were investigated. Pseudo-first/s orders isotherms are applied to determine the efficiency of impregnate solid. The experimental data fitted well with the pseudo-second order model for Cu2+ and Zn2+ adsorption. Maximum capacities for Cu2+ and Zn2+ were 440mmol/kg and 32mmol/kg respectively. However, the adsorption is selective to copper in binary system. Moreover, impregnated solid was also regenerated and reused for subsequent recovery.

The synthesis of mesostructured silicas impregnated with acidic chelators, an acylisoxazolone 3-phenyl-4-benzoyl-5-isoxazolone (HPBI), an acylpyrazolone 1-phenyl-3-methyl-4-stearoyl-5-pyrazolone (HPMSP) and an organophosphoric acid di-(2-ethylhexyl)-phosphoric acid (DEHPA) was undertaken. The different solids were characterized by physico-chemical methods: XRD, FTIR, thermal analysis, TEM, and N2-sorption. The porous integrity of the silica was preserved after impregnation. The amount of ligand was evaluated by UV–Visible analysis of washings, weight loss after calcination and thermal analysis. More than 90% of the ligand used for the impregnation was trapped into the functionalized solids. These materials achieved encouraging extractive performances in removing copper with HPBI below pH 1 and in removing zinc with DEHPA below pH 3 in sulfate media.

The extraction of copper and zinc by mesostructured silicas impregnated with organic acidic chelators, an acylisoxazolone 3-phenyl-4-benzoyl-5-isoxazolone (HPBI), an acylpyrazolone 1-phenyl-3-methyl-4-stearoyl-5-pyrazolone (HPMSP) and an organophosphoric acid di-(2-ethylhexyl)-phosphoric acid (DEHPA) was performed in a sulfate medium. Various factors such as the pH of the aqueous phase, the chelators’ concentration in the silica matrix, the extraction equilibrium time and the extraction capacity of the two cations on silica were studied. The cations were extracted at very acidic pH with very high extraction rates. The stripping of cations was achieved at pH’s that were more acidic than those utilized for the extraction by maintaining the structure intact. Finally, their separation was successfully conducted in the cases of the three chelators.