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This work combines experimental and computational modeling studies for the preparation of a composite of metformin and an organoclay, examining the advantages of a Tunisian clay used for drug delivery applications. The clay mineral studied is a montmorillonite-like smectite (Sm-Na), and the organoclay derivative (HDTMA-Sm) was used as a drug carrier for metformin hydrochloride (MET). In order to assess the MET loading into the clays, these materials were characterized by means of cation exchange capacity assessment, specific surface area measurement, and with the techniques of X-ray diffraction (XRD), differential scanning calorimetry, X-ray fluorescence spectroscopy, and Fourier-transformed infrared spectroscopy. Computational molecular modeling studies showed the surface adsorption process, identifying the clay–drug interactions through hydrogen bonds, and assessing electrostatic interactions for the hybrid MET/Sm-Na and hydrophobic interactions and cation exchange for the hybrid MET/HDTMA-Sm. The results show that the clays (Sm-Na and HDTMA-Sm) are capable of adsorbing MET, reaching a maximum load of 12.42 and 21.97 %, respectively. The adsorption isotherms were fitted by the Freundlich model, indicating heterogeneous adsorption of the studied adsorbate–adsorbent system, and they followed pseudo-second-order kinetics. The calculations of ΔGº indicate the spontaneous and reversible nature of the adsorption. The calculation of ΔH° indicates physical adsorption for the purified clay (Sm-Na) and chemical adsorption for the modified clay (HDTMA-Sm). The release of intercalated MET was studied in media simulating gastric and intestinal fluids, revealing that the purified clay (Sm-Na) and the modified organoclay (HDTMA-Sm) can be used as carriers in controlled drug delivery in future clinical applications. The molecular modeling studies confirmed the experimental phenomena, showing that the main adsorption mechanism is the cation exchange process between proton and MET cations into the interlayer space. [ABSTRACT FROM AUTHOR]

Spherical and rod mesoporous silica nanoparticles with hexagonal mesostructure were prepared using the modified Stöber method. The morphology, size and internal pore structure can be controlled by simple changing of surfactant concentration and water:ethanol molar ratio. Monodispersed spheroid MCM-41 was obtained at 40 °C under basic conditions using cetyltrimethylammonium bromide (C 16 TAB) as template. Obtained materials were characterized by X-ray diffraction (XRD), nitrogen physisorption (BET), transmission electron microscopy (TEM) and scanning electronic microscopy (SEM). The results reveal that the pore volume and surface area increase when the amount of C 16 TAB increases whereas the pore diameter and particle size decrease. However, the use of ethanol as cosolvent led to an increase in the particles’ size. Moreover, the addition of a 3-aminopropyltriethoxysilane greatly influenced the final particle shape. The material was effectively used for the removal of two fluorescent dyes (Hoechst 33342 and rhodamine 6g) from aqueous solution. Adsorption isotherm models, Langmuir, Freundlich and Temkin were used to simulate the equilibrium data. The Langmuir model was found to fit the experimental data better than others models. [ABSTRACT FROM AUTHOR]

The textile industry generates huge volumes of dye-contaminated wastewater. Discharging these effluents into the environment causes many diseases that can be detrimental to human health. Therefore, adsorption of these types of dyes such as methylene blue onto mineral matrices offers an efficient method for pollution remediation. The present investigation is undertaken to test the use of Tunisian clay in raw and sodium form to remove methylene blue from aqueous solution. The experimental data were analysed using the Langmuir, Freundlich, Temkin and Dubinin–Radushkevich isotherms. The equilibrium data fit well to the Langmuir model, and the monolayer adsorption capacity for methylene blue dye is 312.5 and 208.33 mg/g, respectively with sodium clay (MS002-1) and raw clay (MS001-2). [ABSTRACT FROM AUTHOR]

This study emphasized the efficiency of unconventional delignification treatment "Acetocell" as a basic pretreatment to isolate cellulose fiber from Tamarix aphylla 's stem. Chemical proprieties of obtained cellulose were determined and its efficiency for cadmium ions adsorption was evaluated subsequently. Fourier transform infrared spectroscopy (FTIR), X-ray diffraction analysis, thermogravimetric analysis (TGA), Scanning Electron Microscopy (SEM), fluorescence microscope and Morfi were used to analyze the thermochemical and morphological characteristics of the fibers before and after treatment. Cellulose was used as a biosorbent to remove cadmium ions from polluted water. The effects of many parameters on the efficiency removal of cadmium were investigated; the amount of cellulose, the contact time, pH and the initial concentration of cadmium ions. The optimum conditions were 45 mg of adsorbent, 45 mg L−1, 1200 min and pH 8 which provide best adsorption capacity equal to 44.21 mg g−1. The energy value E = 6.65 kJ mol−l which confirm the physical interaction between cellulose-cadmium ions. Then Langmuir, Freundlich, Temkin and Dubinin-Radushkevich models were followed for modeling adsorption. Langmuir isotherm and the pseudo-second order model seems the most suitable which describe better the adsorption of cadmium ions with best R2 values which equal to 0.9937 and 0.9979, respectively. [ABSTRACT FROM AUTHOR]

Porous materials constitute an attractive research field due to their high specific surfaces; high chemical stabilities; abundant pores; special electrical, optical, thermal, and mechanical properties; and their often higher reactivities. These materials are currently generating a great deal of enthusiasm, and they have been used in large and diverse applications, such as those relating to sensors and biosensors, catalysis and biocatalysis, separation and purification techniques, acoustic and electrical insulation, transport gas or charged species, drug delivery, and electrochemistry. Porous carbons are an important class of porous materials that have grown rapidly in recent years. They have the advantages of a tunable pore structure, good physical and chemical stability, a variable specific surface, and the possibility of easy functionalization. This gives them new properties and allows them to improve their performance for a given application. This review paper intends to understand how porous carbons involve the removal of pollutants from water, e.g., heavy metal ions, dyes, and organic or inorganic molecules. First, a general overview description of the different precursors and the manufacturing methods of porous carbons is illustrated. The second part is devoted to reporting some applications such using porous carbon materials as an adsorbent. It appears that the use of porous materials at different scales for these applications is very promising for wastewater treatment industries. [ABSTRACT FROM AUTHOR]

Activated carbon obtained from Opuntia ficus indica by sodium hydroxide activation was employed for the adsorption of p-nitrophenol from water. The activated carbons obtained were characterized by Fourier transforms infrared spectroscopy, sorption of nitrogen, scanning electron microscopy, and Boehm titration. Effects of pH, contact time, amount of adsorbent, and temperature on the adsorption of p-nitrophenol were studied. Adsorption isotherms were analyzed using Freundlich, Langmuir, Temkin, and Dubinin-Radushkevich models, and the thermodynamic parameters have been determined. The adsorption of p-nitrophenol was spontaneous, exothermic, and propitious at 15 °C and adopted the pseudo-second order model, and the most credible isotherm was Langmuir's one. The activated carbon used in this work has good p-nitrophenol adsorption characteristics, and the study of the desorption and reuse of this carbon shows that it retains a removal rate greater than 94% after five cycles of adsorption-desorption. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Mesoporous activated carbon was prepared from date palm petiole. • Activated carbon was used for the removal of IC in batch and fixed bed columns. • A pseudo-second-order model described the kinetics of the adsorption process. • The isotherms were found to be best described by the Langmuir model in batch mode. • Breakthrough curves of Bohart-Adams, Thomas, Yoon-Nelson and Yan models were used. Abstract In this work, the date palm petiole was transformed into activated carbon implying sodium hydroxide as the activating agent. The carbon obtained was exerted for the adsorption of indigo carmine in batch and continuous mode. The properties of activated carbon were established. The effects of pH, adsorbent mass, contact time, initial concentration and temperature on the adsorption of indigo carmine were examined in batch mode. The models of Langmuir, Freundlich, Temkin and Dubinin-Radushkevich were used for modeling adsorption isotherms. The Langmuir model appears to be the most appropriate for describing the adsorption of indigo carmine. The adsorption mechanism was governed by the pseudo-second order model and can be explained by physisorption accompanied by chemisorption. From the thermodynamic point of view, the adsorption was spontaneous and exothermic. In continuous adsorption, The Bohart-Adams model fit perfectly to the initial part of the breakthrough curve ((C t /C 0)<0.5), and the hole curve was well fit by the Yoon-Nelson and Thomas models. [ABSTRACT FROM AUTHOR]

[Display omitted] • Magnetic chitosan-benzoin/fly ash (Cn-Bn-FSH-Fe 3 O 4) was developed. • Cn-Bn-FSH-Fe 3 O 4 was applied for removal of RB19 dye. • Box–Behnken design (BBD) was employed to optimize the adsorption key parameters. • The adsorption isotherm and kinetic were explained by Freundlich and pseudo-second order respectively. • The maximum adsorption capacity of Cn-Bn-FSH-Fe 3 O 4 was found to be 309.6 mg/g. A new composite adsorbent of magnetic chitosan-benzoin/fly ash (Cn-Bn-FSH-Fe 3 O 4) was developed for removal of anionic organic dye (Reactive blue 19: RB19) from aqueous medium. To ascertain the physicochemical characteristics of Cn-Bn-FSH-Fe 3 O 4 , BET, SEM-EDX, FTIR, XRD, and pHpzc test were used. The experimental data was simulated via RSM-BBD to pinpoint the influence of adsorption factors precisely. Laboratory results, including the RSM model outcomes evidenced that the highest RB19 elimination value (97.95 %) was achieved when using Cn-Bn-FSH-Fe 3 O 4 of 0.1 g, solution pH of 4, temperature of 45 °C, and a span time of 32.5 min. The adsorption data were well described by the pseudo-second-order kinetic and Freundlich isotherm models, the monolayer adsorption capacity for RB19 was found to be 309.6 mg/g. The thermodynamic parameters indicated that this adsorption system was endothermic in nature. Thus, this study reaffirms the applicability of the Cn-Bn-FSH-Fe 3 O 4 as promising adsorbent for toxic textile dye removal. [ABSTRACT FROM AUTHOR]