Nigella sativa seeds waste (NSW) was characterized by Fourier transformed infrared spectroscopy, X-ray diffraction, thermogravimetric analysis-TDA, and scanning electron microscopy analysis and used for the adsorptive uptake of methylene blue (MB) from water. The specific surface area of NSW determined by the methylene blue adsorption method was equal to 465.95 m(2)/g. The experimental equilibrium data were investigated using the isotherm equations of Langmuir, Freundlich, Temkin, Redlich-Peterson, Sips, and Radke-Prausnitz. The models of pseudo-first-order, pseudosecond-order, Elovich, intraparticle diffusion, and Avrami were applied for the kinetic data modeling. The maximum MB adsorption capacity of NSW obtained by the Langmuir equation was 149.4 mg/g. The experimental kinetic data fitted very well to the Avrami model. Thermodynamic parameters indicate the spontaneous and endothermic nature of MB adsorption onto NSW. The statistical physics model with single energy was used to determine the adsorption mechanism of MB on NSW. The model confirms the endothermic and physical nature of the process with an anchorage of MB onto NSW. The receptor site density (N-M), the adsorbed dye quantity at saturation (N-sat), the concentration at half-saturation (C-1/2) and the adsorption energy (Delta E) values are equal to 128.23, 141.1 mg/g, 25.4 mg/L and 18.0 kJ/mol, respectively.

Multicomponent sepiolite/magnetite/Prussian blue (PB) were prepared following the nanoarchitectonics approach by incorporating PB pigment to sepiolite fibers previously assembled with magnetite, being later encapsulated within in situ formed calcium alginate beads. These composites were characterized by diverse physicochemical techniques, showing homogeneous dispersion of the assembled nanoparticles (NP) on the surface of sepiolite fibers, the formed Ca-alginate beads exhibiting stability and superparamagnetic response. Based on the affinity of PB toward cesium ions, these beads were tested as selective adsorbent to remove Cs+ from water under different experimental conditions. The maximum adsorption capacity of the beads for Cs+ ions determined by Langmuir equation was around 130 mg/g. The resulting beads maintain a constant adsorption capacity over a large domain of pH, i.e. from 4 to 11. The mechanism of Cs+ removal could be mainly ascribed to the complexing ability of PB, although in minor extent also to cation-exchange properties of sepiolite as well as to interactions with residual carboxylic groups from the alginate biopolymer matrix. The resulting multicomponent composite can be considered as an efficient, economic, ecologic and easily recoverable adsorbent for the removal of Cs+ ions from solution, including radioactive Cs-137, and therefore contributing to environmental remediation of pollution caused in nuclear plants.

Three adsorbents have been developed by encapsulation of organo-activated bentonite (OAB), activated carbon (AC) and organo-activated bentonite/activated carbon (AC-OAB) in cross-linked alginate beads (A) with the aim of using them in the removal of bisphenol A (BPA) and 2.4.5-trichlorophenol (TCP). The adsorption capacities of the three adsorbents were investigated in order to choose the best adsorbent for BPA and TCP. The alginate/activated carbon beads (A-AC) exhibit the maximum BPA and TCP adsorption capacities (419.3 and 444.7 mg/g at 25 degrees C, respectively). In the binary system, a decrease was observed at the adsorbed amount to 291.5 mg/g for BPA and 430.2 mg/g for TCP. The adsorption of BPA and TCP by A-AC composite beads was studied and the effects of solution pH value, temperature and contact time on the adsorption were investigated. Results revealed that BPA and TCP adsorption kinetics onto A-AC are best described by the pseudo-second order model, and the equilibrium adsorption data are well fitted to both Langmuir and Freundlich models. The zero point charge determination (pH(PZC)), the scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) analysis were carried out. The A-AC composite was used for six cycles without significant adsorptive performance loss. Therefore, the ecofriendly prepared A-AC adsorbent was considered as highly recyclable and efficient adsorbent for BPA and TCP pollutants.

Alginate gel (A) and activated carbon prepared from apricot stone (AC) were combined to prepare activated carbon alginate beads (A-AC) adsorbent and used to remove bisphenol A (BPA) and 2,4,5-trichlorophenol (TCP) from solution in single and binary system. The zero point charge determination (pHpzc), the scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) analysis were carried out. The effects of pH solution (2-11), temperature (15 degrees C, 25 degrees C, 35 degrees C, and 45 degrees C), initial concentration (15-400 mg/L) and contact time were investigated. The adsorption processes fitted well with the pseudo-second-order kinetic model and Langmuir isotherm. Results showed that the maximum adsorption capacities of A-AC for the adsorption of BPA and TCP in single system are 419.3 and 444.3 mg/g at 25 degrees C, respectively. In the binary system, a decrease was observed at the adsorbed amount to 291.2 mg/g for BPA and 430.2 mg/g for TCP. The thermodynamic parameters confirmed that the adsorption reaction was spontaneous and endothermic in nature. Desorption tests showed that the removal efficiency of A-AC for BPA and TCP decreased slightly after six regeneration cycles and were maintained at 83.2% and 77.6%, respectively. The results suggest that the use of A-AC beads is a feasible strategy for the removal of BPA and TCP.

Magnetic alginate beads (A-Fe2O3) and magnetic alginate functionalized multiwalled carbon nanotubes beads (A-F-Fe2O3) were synthesized using citrate coated maghemite nanoparticles (γ-Fe2O3). Vibrating sample magnetometry analysis showed that the mass saturation magnetization of A-F-Fe2O3, A-Fe2O3, and γ-Fe2O3 is equal to 27.16, 29.06, and 42.63 emu·g−1, respectively. Compared with A-Fe2O3 beads, A-F-Fe2O3 beads showed a better adsorption performance for MB removal with a maximum monolayer adsorption capacity of qm = 905.5 mg·g−1. The adsorption studies revealed that the data of MB adsorption isotherm onto A-F-Fe2O3 were well fitted by Freundlich model. The adsorption was ionic strength and initial dye concentration-dependent. The beads presented high stability of MB adsorption capacity in a large domain of pH. Adsorption kinetic data followed the intraparticle diffusion model. Regeneration experiments were performed using five different desorbing agent. The findings reveal that magnetic A-F-Fe2O3 beads present an ideal and cost effective adsorbent in large-scale application as it demonstrated high affinity and reusability for methylene blue dye and facilitate an easy separation after treatment.

In the present study, new adsorbent beads of alginate (A)/maghemite nanoparticles (γ-Fe2O3)/functionalized multiwalled carbon nanotubes (f-CNT) were prepared and characterized by several techniques, e.g., N2 adsorption-desorption isotherms, Fourier transformed infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA/DTG), scanning electron microscopy (SEM), and vibrating sample magnetometry (VSM) and further tested for the adsorption of the dye methylene blue (MB) from water. The beads (A/γ-Fe2O3/f-CNT) presented a relatively low BET specific surface area value of 59 m2g−1. The magnetization saturation values of A/γ-Fe2O3/f-CNT beads determined at 295 K was equal to 27.16 emu g−1, indicating a magnetic character. The time needed to attain the equilibrium of MB adsorption onto the beads was estimated within 48 h. Thus, several kinetic and isotherm equation models were used to fit the kinetic and equilibrium experimental results. The number of adsorbed MB molecules per active site, the anchorage number, the receptor sites density, the adsorbed quantity at saturation, the concentration at half saturation and the molar adsorption energy were quantified using the monolayer model. The calculated negative ΔG0 and positive ΔH0 values suggested the spontaneous and endothermic nature of the adsorption process. In addition, A/γ-Fe2O3/f-CNT composites can be used at least for six times maintaining their significant adsorptive performance and could be easily separated by using a magnet from water after treatment.

Magnetic beads (AO-γ-Fe2O3) of alginate (A) impregnated with citrate coated maghemite nanoparticles (γ-Fe2O3) and oxidized multiwalled carbon nanotubes (OMWCNTs) were synthesized and used as adsorbent for the removal of methylene blue from water. The XRD analysis revealed that the diameter of γ-Fe2O3 is 10.24 nm. The mass saturation magnetization of AO-γ-Fe2O3 and γ-Fe2O3 were found to be 27.16 and 42.63 emu·g-1, respectively. The adsorption studies revealed that the data of MB isotherm were well fitted to the Freundlich model. The Langmuir isotherm model exhibited a maximum adsorption capacity of 905.5 mg·g-1. The adsorption was very dependent on initial concentration, adsorbent dose, and temperature. The beads exhibited high adsorption stability in large domain of pH (4-10). The thermodynamic parameters determined at 283, 293, 303, and 313 K revealed that the adsorption occurring was spontaneous and endothermic in nature. Adsorption kinetic data followed the intraparticle diffusion model. The AO-γ-Fe2O3 beads were used for six cycles without significant adsorptive performance loss. Therefore, the eco-friendly prepared AO-γ-Fe2O3 beads were considered as highly recyclable and efficient adsorbent for methylene blue as they can be easily separated from water after treatment.

A new biomaterial (A-OB) consisting of alginate and organobentonite was prepared according to the ionic gelation method. Physical characteristics of A-OB were studied using pHPZC and FTIR. Bisphenol A, one of endocrine disrupting compounds (EDCs), was used as model water organics pollutants. Factors affecting BPA sorption, such as pH, and concentration of BPA solution were extensively investigated. It was found from the study that the sorption of BPA by the biomaterial beads is pH-dependent and concentration of solution. The adsorption mechanism of BPA onto A-OB was evaluated in terms of kinetics, and equilibrium. The data obtained from the batch sorption experiments were well fitted by pseudo-second-order. The Langmuir and Freundlich isotherm models were used to describe equilibrium data. Resume: Un nouveau biomateriau d’alginate/organobentonite (A-OB) a ete prepare selon la methode de gelification ionique, caracterise par pHPZC et IRTF. L’etude de l’adsorption d’un perturbateur endocrinien bisphenol A (BPA) en systeme batch, nous a permis de constater que leur elimination est depond du pH et de la concentration de solution de BPA. L'etude cinetique de l'adsorption de BPA sur l’A-OB pourrait etre bien decrite avec le modele du cinetique pseudo-second ordre. L’isotherme de Langmuir ainsi que de Freundlich sont favorable pour l’adsorption de BPA sur l’adsorbant A-OB.

Dans le present travail, differents biofilms a base de la gelatine associee a la cellulose, la carboxymethylcellulose, et la methylcellulose sont prepares. Il est observe que la reticulation en presence du glutaraldehyde apporte une meilleure propriete mecanique tout en augmentant la resistance thermique, et une diminution de l’hydrosolubilite de biopolymer utilise. Ces biofilms sont aussi modifies par l’addition du glycerol ce qui entraine une diminution de la fragilite et du retrait. Le test de gonflement montre que l’association de la carboxymethylcellulose a la gelatine presente des proprietes d’absorption importantes, ce qui fait un bon candidat pour absorber les exsudats afin de preserver les berges de la plaie et la peau peri-lesionnelle. Toutefois, l’etude en fonction de la temperature montre qu’a temperature ambiante, les taux de gonflement (Gmax) correspondants sont inferieurs a ceux obtenus a 37°C (temperature du corps humain). Le dosage par spectrophotometrie UV-vis indique qu’il existe une liberation considerable de constituant(s) de biofilms a 37°C, ce qui permettre une meilleure cicatrisation en maintenant un milieu humide favorable sur le lit de la plaie.

Today toxic phenolic compounds are a major source of pollution and are mainly the result of various industrial wastes such as plastics, polymers, insecticides, etc. In this context, the originality of our study is a first as we used a new composite material assembled by mixing activated carbon (AC), organo activated bentonite (OAB), and alginate (A). The prepared adsorbent materials were characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and point of zero charge (pH(PZC)). The influence of various factors such as contact time, pH, adsorbate concentration, and temperature on the adsorption of bisphenol A (BPA) and 2,4,5-trichlorophenol (TCP) has been investigated. The equilibrium data were fitted well by Freundlich isothermal model and the maximum adsorptions of BPA and TCP onto alginate/organo activated bentonite/activated carbon beads (A-OAB-AC), were 368.2 and 385.1 mg.g(-1), respectively. The adsorption of BPA and TCP was observed to follow pseudo-second order mechanism as well as the thermodynamic parameters confirm also endothermic spontaneous and physiosorption processes. In addition, the resulting adsorbent reusability was demonstrated by at least six cycles, indicating that the A-OAB-AC can be used as a promising adsorbent for removal of toxic pollutants from aqueous solutions.

The organo-acid-activated bentonite (OAB) was prepared and characterized by SEM, XRD, FTIR, pH(PZC) and BET. Then the OAB was employed as adsorbent for the removal of bisphenol A (BPA) and 2,4,5-trichlorophenol (TCP) from aqueous solutions. The adsorption performances of OAB were investigated by batch mode experiments with respect to pH, temperature, initial concentration, contact time and competitive adsorption. The Langmuir model describes better the results of BPA adsorption while the results of TCP are best fitted to Freundlich model. The maximum adsorption capacities are found to be 127.7 and 244.6 mg/g for BPA and TCP, respectively. The kinetic properties were well described by the pseudo-second-order equation. Thermodynamic parameters suggest that the adsorption process of BPA and TCP onto organoclay (OAB) are physisorption, spontaneous and exothermic. In binary solutions, BPA and TCP show competitive adsorption. Hydrophobic interaction play an important role during the sorption process. In addition, OAB could be regenerated and reused for adsorption of BPA/TCP again.

Two prepared adsorbents, namely, calcined ZnAl-layered double hydroxide and K10 montmorillonite intercalated with cetyltrimethyl-ammonium bromide cations are used in diclofenac sodium adsorption under the batch reactor operations. The pseudo-second-order model describes better the results of the kinetics. Fitting parameters revealed that the rate of adsorption increased with the increase in diclofenac sodium concentration and decrease in background electrolyte concentration and temperature, while the solution pH did not have a significant effect. The maximum adsorption capacities of diclofenac obtained by Langmuir model are found to be 55.46 and 737.02 mg/g for K10 montmorillonite intercalated with cetyltrimethyl-ammonium bromide cations and ZnAl-C LDH, respectively. The results of adsorption–desorption cycles revealed that ZnAl-C LDH and K10 montmorillonite intercalated with cetyltrimethyl-ammonium bromide cations have an excellent potential to be used as an economical adsorbent for the removal of diclofenac sodium from water.

In this study, acid-activated organobentonite (OAB), calcium alginate (A) and calcium alginate/acid-activated organobentonite composite beads (A-OAB) were prepared and applied for the removal of methylene blue from solutions in batch system. The zero point charge of pH (pHpzc), Scanning electron microscopy (SEM) and Fourier transformed infrared spectroscopy (FTIR) analysis were carried out. The effects of pH solution (2-11), temperature (15, 25, 35 and 45°C), initial concentration (20-500mg/L), and contact time were investigated. The adsorption processes fitted well with the pseudo-second-order kinetic model and both models Langmuir and Chapman isotherms. Results showed that the maximum adsorption capacities of (OAB), (A) and (A-OAB) for the adsorption of MB were 263.80, 483.6 and 799.43mg/g at 25°C, respectively. Thermodynamic studies showed spontaneous and endothermic nature of the overall adsorption process. Desorption tests showed that the removal efficiency of MB decreased from 95 to 89.7% after six regeneration cycles for (A-OAB). From this, (A-OAB) can be utilized as an economical adsorbent for the removal of basic dyes from the contaminated waste water.

In this paper, we addressed the issue of using organo-K10 montmorillonite as adsorbent of DS to remove it from aqueous environment. An organo-K10 montmorillonite (MK10-C16) was prepared by intercalating the organic cation cetyltrimethylammonium bromide (C16) in a K10 montmorillonite (MK10), than characterized using XRD analytical technique. The organo-K10 montmorillonite displayed enhanced affinity for the DS in water. Using a linear regression, the pseudo-second-order model describes better the results of the kinetics. The adsorption data fitted well with Langmuir isotherm. The maximum adsorption capacity of diclofenac is estimated to be 63.33 mgg-1. The results revealed that MK10-C16 have a high potential to be used as adsorbent for the removal of DS from aqueous solution.