Influence of the chain length of surfactant in the modification of zeolites and clays. Removal of atrazine from water solutions

Influence of the chain length of surfactant in the modification of zeolites and clays. Removal of atrazine from water solutionsRemoval potentials of a surfactant modified zeolite (SMZ) and clay (SMC) for atrazine adsorption were evaluated. Materials were modified with hexadecyl trimethyl ammonium bromide (HDTMABr) and benzyl octadecyl dimethyl ammonium (BODA) chloride considering the critical micellar concentration (CMC) of each one (0.94 and 0.041 meq/L, respectively). The influence of the surfactant was analyzed in detail, particularly the formation of surfactant layers (complete or partial) connected with the length of the surfactant tail (16 and 18 methyl groups or number of carbons in the chain). Raw materials were characterized by XRD and Fourier transform infrared spectroscopy (FTIR), SMZ and SMC were analyzed by FTIR. Results obtained from kinetic adsorption experiments shown that equilibrium time is less for materials modified with HDTMA (8 h) than materials with BODA (10 and 12 h). Materials modified with the largest chain surfactant (BODA) showed more resistance to atrazine masse transference. The chemisorption was presented in the adsorption mechanisms of atrazine and adsorbent materials. Based on the results of adsorption isotherms Langmuir isotherms showed the better correlation coefficients value. The qmax is greater for materials modified with BODA (0.9232 and 4.2448 mg/g) than for materials modified with HDTMA (0.6731 and 3.9121 mg/g). Therefore, SMZ and SMC modified with the largest chain surfactant has more affinity for the pesticide. The removal process at high concentration of atrazine depends of the partition process but at lower concentration, it occurs not only by this process but also by absorption process

Influence of the chain length of surfactant in the modification of zeolites and clays. Removal of atrazine from water solutions

Influence of the chain length of surfactant in the modification of zeolites and clays. Removal of atrazine from water solutionsRemoval potentials of a surfactant modified zeolite (SMZ) and clay (SMC) for atrazine adsorption were evaluated. Materials were modified with hexadecyl trimethyl ammonium bromide (HDTMABr) and benzyl octadecyl dimethyl ammonium (BODA) chloride considering the critical micellar concentration (CMC) of each one (0.94 and 0.041 meq/L, respectively). The influence of the surfactant was analyzed in detail, particularly the formation of surfactant layers (complete or partial) connected with the length of the surfactant tail (16 and 18 methyl groups or number of carbons in the chain). Raw materials were characterized by XRD and Fourier transform infrared spectroscopy (FTIR), SMZ and SMC were analyzed by FTIR. Results obtained from kinetic adsorption experiments shown that equilibrium time is less for materials modified with HDTMA (8 h) than materials with BODA (10 and 12 h). Materials modified with the largest chain surfactant (BODA) showed more resistance to atrazine masse transference. The chemisorption was presented in the adsorption mechanisms of atrazine and adsorbent materials. Based on the results of adsorption isotherms Langmuir isotherms showed the better correlation coefficients value. The qmax is greater for materials modified with BODA (0.9232 and 4.2448 mg/g) than for materials modified with HDTMA (0.6731 and 3.9121 mg/g). Therefore, SMZ and SMC modified with the largest chain surfactant has more affinity for the pesticide. The removal process at high concentration of atrazine depends of the partition process but at lower concentration, it occurs not only by this process but also by absorption process

Novel tuffite/Fe-Cu oxides nanocomposite with functionality for dye removal in aqueous solution

Fe-Cu oxides nanoparticles were embedded on tuffite (TUF) mineral by means of a simple immersion-ion impregnation, followed by a reduction reaction, methodology. TUF/Fe-Cu nanocomposite characteristics were investigated by XRD, TEM, BET, SEM, FT-IR spectroscopy and pHzpc method. Fe-Cu nanostructures with mean sizes between 10 and 20 nm were effectively supported on TUF. Because of its functional properties, the nanocomposite was studied as adsorbent material for the degradation of Malachite Green (MG) organic dye in aqueous solution. The adsorption kinetic data was well-fitted to pseudo first-order model, indicating physisorption as the main mechanism of adsorption. High pH and temperature of the solution favored malachite green adsorption. The adsorption process was spontaneous and endothermic. In comparative sorption experiments with different dyes, the nanocomposite showed better removal capacities for cationic and basic than for anionic and acid dyes. Langmuir, Freundlich, Langmuir-Freundlich and Temkin models were applied to evaluate the isotherms, resulting in an adsorption capacity of 376.66 mg/g, which is above most of the adsorbent materials so far employed for malachite green degradation in aqueous solution. Therefore, this novel, easy to prepare and low-cost nanocomposite proved to have synergic functionality as an efficient adsorbent material for cationic organic dyes.UAEM/2708/2013 and 3688/2014/CIB projects. Scholar-ship Grant No. 289993CONACYT

Reuse of sustainable materials for xylenol orange dye and copper (II) ion ammoniacal removal

Reuse of sustainable materials for xylenol orange dye and copper (II) ion ammoniacal removalWater pollution caused by heavy metals and organic compounds is an environmental problem with negative impact, making the restoration of water quality a priority. In this paper, the adsorption of xylenol orange dye (XO) on vitreous tuff mineral (VT) was studied. It was established that the adsorption capacity of VT was 45.17 mg/g. The removal was carried out by interactions between active sites on the surface of the material and the functional groups of the dye. The solid waste obtained from this process (VTXO) was reused as adsorbent material for Cu removal in the form of the complex Cu-NH3 because this process was done in an ammoniacal medium. It was found that the adsorption capacity of this new material was 33.09 mg/g. In a previous research, VT mineral was used to remove crystal violet (CV) instead of XO. The solid waste of this last process (VTCV) was also applied for Cu-NH3 removal, in order to compare the adsorption capacity of VT after the adsorption of two different kinds of dyes. The adsorption capacity of VTXO was lower than that of VTCV (71.23 mg/g). In both processes, adsorption kinetic was well described by a chemical adsorption onto a heterogeneous surface. The equilibrium time for XO removal was 50 min and 80 min for Cu-NH3. The experimental design stated that the maximum adsorption capacity was reached when the initial concentration was 6400 mg/L and the solid-liquid ratio was 10 g/L. The system that requires the least amount of adsorbent was the counter flow batch. Finally, it was possible to estimate the behavior of the system on a higher scale. This research provides an efficient and economical alternative to treat water contaminated with dyes and cooper in an ammoniacal medium using the same material in both processes, one after the other

Efficient removal of crystal violet dye from aqueous solutions by vitreous tuff mineral

Textural, structural and morphological characteristics of the vitreous tuff were determined by means of several physicochemical techniques. The nitrogen adsorption isotherm at 77K was fitted with the Brunnauer–Emmet–Teller model and together with the results of the average pore distribution showed a mesoporous material. Samples of vitreous tuff were used as adsorbent to study the removal of crystal violet from aqueous solution. The presence of -OH moieties in the material seems to be responsible for the removal of the dye showing that vitreous tuff can be used as an organic dye adsorbent material. The pseudo-second-order model was the best fit model for describing the sorption process of crystal violet; intraparticle diffusion being the controlling step in the process. The experimental adsorption isotherm was fitted with Langmuir, Freundlich and Langmuir–Freundlich models, showing better correlation with the second one. The adsorption capacity was 170.01 mg/g, being among the highest compared with other inorganic and organic common sorbent materials. The design of single stage of the adsorber can predict the behaviour to potential scale up. This mineral has a very good potential as an adsorbent material for organic dyes.CONACYT scholarship [Grant No. 507915], Universidad Autónoma del Estado de México, project 3211–2012 and PROMEP/103.5/13/6535 project

Cu(II) adsorption from aqueous solutions using the inner and outer portions of sugarcane bagasse

Artículo publicado en revista indizadaIn the present work, the adsorption capacity of internal and external portions of treated sugarcane bagasse (SCB) to remove Cu(II) from aqueous solution was evaluated. In order to reuse this solid waste as an effective adsorption material, both portions were treated with three different solutions (hot water, ethanol and NaOH) to remove sugar, external gummy tissue and impurities. Adsorption experiments were carried out in a batch system at room temperature. The kinetic data were fitted to pseudo-second order and Elovich models for the internal portion, and to the Elovich model for the external portion reaching equilibrium times from 8 to 24 h. Freundlich and Langmuir–Freundlich models described well the adsorption behavior of all systems. The compositional differences of the two portions of SCB and the surface chemistry were analyzed. Material characterization by scanning electron microscopy, Fourier transformed infrared spectroscopy, and X-ray photoelectron spectroscopy demonstrated morphologic and chemical modifications of the material after each treatment. Results showed that external SCB treated with a sodium hydroxide solution and internal SCB treated with ethanol solution were the best adsorbent materials, and provided a surface with more affinity to remove Cu(II).CONACYT-280518 "Fortalecimiento y desarrollo de la infraestructura científica y tecnológica" CONACYT beca escolar No 44972

Study of the influence of Xanthate Derivative Structures on Copper Sulfide Mineral Adsorption Under Acidic Conditions

Artículo de investigación en revista indizadaAdsorption of commercial xanthate derivatives on copper sulfide mineral (covellite, CuS) was studied by kinetics and isotherm adsorption experiments. The adsorption of xanthate derivatives was confirmed by FTIR (Fourier transform infrared spectroscopy) and XPS (X-ray photoelectron spectroscopy) results. Experiments were performed with two different xanthate derivatives, C-4410 (O-pentyl S-2-propenyl ester) and C-4940 (isobutyl xanthogen ethyl formate), on individual doses of 0.05 g of powdered covellite. It was found that the equilibrium times at pH 2, 4, and 6 were different for both xanthate derivatives. The shortest times were achieved at pH 2 and 4. The results suggest that C-4110 can be used as collector in a wide range of pH, while C-4940 is limited to lower pH values. Pseudo first- and pseudo second-order kinetics models were thus applied to the experimental data for pH 2. The information obtained from the kinetics models combined with XPS allowed proposing the adsorption mechanism for the covellite-xanthate derivative pair. The adsorption takes place through a non-covalent interaction for C-4410 and chemisorption process for C-4940. The best-fitting isotherm models for C-4410 and C-4940 adsorption were Redlich–Peterson and Freundlich, respectively, which yield a maximum adsorption capacity of 57.07 mg g 1 for C-4410 and 44.62 mg g 1 for C-4940.CONACYT CB-254952-201

Efficient coal concentration using a short-chain amine-type compound as collector reagent: Flotation and optimization studies

This work presents the flotation of a sub-bituminous coal using 1-butylamine as a short-chain amine collector. The flotation results have been obtained with 1-butylamine (coal yield: 100%) and compared with those achieved with a quaternary amine (coal yield: 95.4%), kerosene (coal yield: 100%) and diesel (coal yield: 95.7%). The best results have been obtained with 1-butylamine. Less depressant effect has been observed with 1-butylamine. The FTIR signals have been attenuated when the coal is conditioned with 1-butylamine. Zeta potential measurements have also been changed after conditioning. The contact angle of water and graphite has decreased from 82.3° to 32.2°. An optimization has been performed using a Box-Behnken experimental design. Flotation has significantly affected by time and collector dosage. The pH is not a significant factor. The optimal conditions for the best efficiency using 1-butylamine as a collector are 2.0 min of flotation and 10-3 mol/L of collector

Novel tuffite/Fe-Cu oxides nanocomposite with functionality for dye removal in aqueous solution

Fe-Cu oxides nanoparticles were embedded on tuffite (TUF) mineral by means of a simple immersion-ion impregnation, followed by a reduction reaction, methodology. TUF/Fe-Cu nanocomposite characteristics were investigated by XRD, TEM, BET, SEM, FT-IR spectroscopy and pHzpc method. Fe-Cu nanostructures with mean sizes between 10 and 20 nm were effectively supported on TUF. Because of its functional properties, the nanocomposite was studied as adsorbent material for the degradation of Malachite Green (MG) organic dye in aqueous solution. The adsorption kinetic data was well-fitted to pseudo first-order model, indicating physisorption as the main mechanism of adsorption. High pH and temperature of the solution favored malachite green adsorption. The adsorption process was spontaneous and endothermic. In comparative sorption experiments with different dyes, the nanocomposite showed better removal capacities for cationic and basic than for anionic and acid dyes. Langmuir, Freundlich, Langmuir-Freundlich and Temkin models were applied to evaluate the isotherms, resulting in an adsorption capacity of 376.66 mg/g, which is above most of the adsorbent materials so far employed for malachite green degradation in aqueous solution. Therefore, this novel, easy to prepare and low-cost nanocomposite proved to have synergic functionality as an efficient adsorbent material for cationic organic dyes.UAEM/2708/2013 and 3688/2014/CIB projects. Scholar-ship Grant No. 289993CONACYT

Efficient removal of crystal violet dye from aqueous solutions by vitreous tuff mineral

Textural, structural and morphological characteristics of the vitreous tuff were determined by means of several physicochemical techniques. The nitrogen adsorption isotherm at 77K was fitted with the Brunnauer–Emmet–Teller model and together with the results of the average pore distribution showed a mesoporous material. Samples of vitreous tuff were used as adsorbent to study the removal of crystal violet from aqueous solution. The presence of -OH moieties in the material seems to be responsible for the removal of the dye showing that vitreous tuff can be used as an organic dye adsorbent material. The pseudo-second-order model was the best fit model for describing the sorption process of crystal violet; intraparticle diffusion being the controlling step in the process. The experimental adsorption isotherm was fitted with Langmuir, Freundlich and Langmuir–Freundlich models, showing better correlation with the second one. The adsorption capacity was 170.01 mg/g, being among the highest compared with other inorganic and organic common sorbent materials. The design of single stage of the adsorber can predict the behaviour to potential scale up. This mineral has a very good potential as an adsorbent material for organic dyes.CONACYT scholarship [Grant No. 507915], Universidad Autónoma del Estado de México, project 3211–2012 and PROMEP/103.5/13/6535 project