Nanocrystalline Akaganeite as Adsorbent for Surfactant Removal from Aqueous Solutions.
Ontology highlight
ABSTRACT:
SUBMITTER: Kyzas GZ
PROVIDER: S-EPMC5452109 | biostudies-other | 2013 Jan
REPOSITORIES: biostudies-other
Similar Datasets
Project description:The rapid increase of industrial activities leads to serious environmental pollution, especially, in aqueous systems and particularly with heavy metals. Cadmium, one of the most poisonous elements, is rapidly accumulated in the human body, therefore, the efficient removal of cadmium ions from wastewater is an urgent need. Coordination networks (CNs) and its subdivision metal-organic frameworks (MOFs), are structured porous composites which present various special properties. In this work two CNs were used as adsorbent materials for the removal of Cd(II) ions from aqueous solutions. By the reaction of CoSO4·7H2O and NiSO4·7H2O with N,N-bis(phosphonomethyl)glycine (Gly) in hydrothermal conditions two CNs-Co-Gly and Ni-Gly- were synthesized, respectively. Cadmium adsorption onto the studied CNs was conducted in batch mode, and the effect of pH, initial concentration, contact time, temperature and sorbent weight on the sorption process were investigated. Parametric Method 3 (PM3)semi-empirical analyses of the CNs' structural properties were performed in order to predict the adsorption properties. For this reason, two octahedral models were calculated and computational predictions were compared with the experimental results. Both computational and experimental adsorption studies found that Ni-Gly presents higher affinity for cadmium ions. Moreover, the adsorbent materials can be readily regenerated and recycled without significant loss of cadmium uptake capacity.
| S-EPMC7279495 | biostudies-literature
Project description:In this study, sodium alginate was employed as a starting material for preparing two kinds of biocompatible adsorbents, including calcium alginate hydrogel beads and magnetic hydrogel beads. Fourier transform infrared spectroscopy, X-ray diffraction pattern, and scanning electron microscopy/energy-dispersive X-ray techniques were used to characterize the prepared adsorbents. The performance of the prepared adsorbents for the removal of methyl violet from aqueous solution was studied in detail. Both kinetics and equilibrium aspects of methyl violet adsorption were investigated, and the obtained equilibrium and kinetics data were described with various adsorption models. The effects of initial dye concentration, adsorbent dosage, and temperature on adsorption performance were investigated. Thermodynamic parameters of adsorption were obtained as well.
| S-EPMC6289535 | biostudies-literature
Project description:This study aimed to understand the adsorption process of cephalexin (CPX) from aqueous solution by a biochar produced from the fiber residue of palm oil. Scanning electron microscopy, Fourier transform infrared spectroscopy, Boehm titration, and the point of zero charge were used to characterize the morphology and surface functional groups of the adsorbent. Batch tests were carried out to evaluate the effects of the solution pH, temperature, and antibiotic structure. The adsorption behavior followed the Langmuir model and pseudo-second-order model with a maximum CPX adsorption capacity of 57.47 mg g-1. Tests on the thermodynamic behavior suggested that chemisorption occurs with an activation energy of 91.6 kJ mol-1 through a spontaneous endothermic process. Electrostatic interactions and hydrogen bonding represent the most likely adsorption mechanisms, although π-π interactions also appear to contribute. Finally, the CPX removal efficiency of the adsorbent was evaluated for synthetic matrices of municipal wastewater and urine. Promising results were obtained, indicating that this adsorbent can potentially be applied to purifying wastewater that contains trace antibiotics.
| S-EPMC8199501 | biostudies-literature
Project description:A bismuth oxyiodide (BiOI) photocatalyst with excellent sunlight-driven performance was synthesized by a solvothermal route without the addition of surfactants or capping agents. The prepared photocatalyst exhibited a tetragonal phase with an energy band gap of 2.15 eV. The efficiency of the photocatalyst was elucidated by monitoring the photodegradation of organic dyes and antibiotics. The BiOI photocatalyst provided a 95% removal of norfloxacin (NOR) antibiotics under visible light illumination. Interestingly, the complete removal of Rhodamine B (RhB) dye was achieved after 80 min of natural sunlight irradiation. The photodegradation reaction followed the first-order reaction. Both photo-generated holes and electrons play vital roles in the photodegradation of the pollutant. The BiOI photocatalyst remains stable and still shows a high efficiency even after the fifth run. This confirms the great cycling ability and high structural stability of the photocatalyst. The prepared BiOI catalyst, with a high surface area of 118 m2 g-1, can act as an excellent adsorbent as well. The synergistic effect based on both adsorption and photocatalysis is a key factor in achieving a very high removal efficiency. The photoactivity under sunlight is higher than that observed under visible light, supporting the practical use of the BiOI photocatalyst for the removal of organic pollutants in wastewater through the utilization of abundant solar energy.
| S-EPMC8471800 | biostudies-literature
Project description:Motivated by the possibility of enhancing aerosol drug delivery to mucus-obstructed lungs, the spreading of a drop of aqueous surfactant solution on a physically entangled aqueous poly(acrylamide) solution subphase that mimics lung airway surface liquid was investigated. Sodium dodecyl sulfate was used as the surfactant. To visualize spreading of the drop and mimic the inclusion of a drug substance, fluorescein, a hydrophilic and non-surface-active dye, was added to the surfactant solution. The spreading progresses through a series of events. Marangoni stresses initiate the convective spreading of the drop. Simultaneously, surfactant escapes across the drop's contact line within a second of deposition and causes a change in subphase surface tension outside the drop on the order of 1 mN/m. Convective spreading of the drop ends within 2-3 s of drop deposition, when a new interfacial tension balance is achieved. Surfactant escape depletes the drop of surfactant, and the residual drop takes the form of a static lens of nonzero contact angle. On longer time scales, the surfactant dissolves into the subphase. The lens formed by the water in the deposited drop persists for as long as 3 min after the convective spreading process ends due to the long diffusional time scales associated with the underlying entangled polymer solution. The persistence of the lens suggests that the drop phase behaves as if it were immiscible with the subphase during this time period. Whereas surfactant escapes the spreading drop and advances on the subphase/vapor interface, hydrophilic dye molecules in the drop do not escape but remain with the drop throughout the convective spreading. The quasi-immiscible nature of the spreading event suggests that the chemical properties of the surfactant and subphase are much less important than their physical properties, consistent with prior qualitative studies of spreading of different types of surfactants on entangled polymer subphases: the selection of surfactant for pulmonary delivery applications may be limited only by physical and toxicological considerations. Further, the escape of surfactant from individual drops may provide an additional spreading mechanism in the lung, as hydrodynamic and/or surface pressure repulsions may drive individual droplets apart after deposition.
| S-EPMC3959907 | biostudies-literature
Project description:Phase segregation in aqueous biphasic systems (ABS) composed of four hydrophilic ionic liquids (ILs): 1-butyl-3-methylimidazolium methylsulfate and 1-ethyl-3-methylimidazolium methylsulfate (C(n)C?im C?SO?, n = 2 and 4), tributylmethyl phosphonium methylsulfate (P???? C?SO?) and methylpyridinium methylsulfate (C?Py C?SO?) and two high charge density potassium inorganic salts (K?CO? and K?HPO?) were determined by the cloud point method at 298.15 K. The influence of the addition of the selected inorganic salts to aqueous mixtures of ILs was discussed in the light of the Hofmeister series and in terms of molar Gibbs free energy of hydration. The effect of the alkyl chain length of the cation on the methylsulfate-based ILs has been investigated. All the solubility data were satisfactorily correlated to several empirical equations. A pesticide (pentachlorophenol, PCP) extraction process based on the inorganic salt providing a greater salting out effect was tackled. The viability of the proposed process was analyzed in terms of partition coefficients and extraction efficiencies.
| S-EPMC3821652 | biostudies-literature
Project description:For realization of a wearable artificial kidney based on regeneration of a small volume of dialysate, efficient urea removal from dialysate is a major challenge. Here a potentially suitable polymeric sorbent based on phenylglyoxaldehyde (PGA), able to covalently bind urea under physiological conditions, is described. Sorbent beads containing PGA groups were obtained by suspension polymerization of either styrene or vinylphenylethan-1-one (VPE), followed by modification of the aromatic groups of poly(styrene) and poly(VPE) into PGA. It was found that PGA-functionalized sorbent beads had maximum urea binding capacities of 1.4-2.2 mmol/g and removed ∼0.6 mmol urea/g in 8 h at 37 °C under static conditions from urea-enriched phosphate-buffered saline, conditions representative of dialysate regeneration. This means that the daily urea production of a dialysis patient can be removed with a few hundred grams of this sorbent which, is an important step forward in the development of a wearable artificial kidney.
| S-EPMC7027168 | biostudies-literature
Project description:In this research, the maximum retention and wetting behavior of surfactant solutions (N-200, N-300, Tween-80, Morwet EFW, DTAB, SDS) on the surfaces of tea leaves was investigated based on surface free energy, surface tension, the contact angle, adhesion work, and adhesion force. The results showed that the contact angles of all surfactant solutions were kept constant with low adsorption at the tea leaf-liquid interfaces below 0.005%. With an increase in concentration, the contact angle of Tween-80 decreased sharply because the adsorption of molecules at the solid-liquid interfaces (ΓSL') was several times greater than that at the liquid-air interfaces (ΓLV). Adhesion work decreased sharply and then reached a minimum at the critical micelle concentration (CMC), but then increased until reaching a constant. Moreover, a high adhesion force did not indicate better wettability, as it does with rose petals and peanut leaves. For tea leaf surfaces, an increase in the contact angle brought about an increase in the adhesion force. In addition, the maximum retention for Morwet EFW is at different concentrations compared to N-200, N-300, Tween-80, DTAB, and SDS, where the maximum retention of Morwet EFW on tea leaves was 6.05 mg/cm2 at 0.005%.According to the mechanisms of wetting behavior on plant surfaces, a recipe for pesticide formulation can be adjusted with better wettability to reduce loss, improve utilization efficiency, and alleviate adverse effects on the environment.
| S-EPMC6600537 | biostudies-literature
Project description:In this study, the removal of nickel (Ni(II)) by adsorption from synthetically prepared solutions using natural bentonites (Lieskovec (L), Hliník nad Hronom (S), Jelšový Potok (JP), and Stará Kremni?ka (SK)) was investigated. All experiments were carried out under batch processing conditions, with the concentration of Ni(II), temperature, and time as the variables. The adsorption process was fast, approaching equilibrium within 30 min. The Langmuir maximum adsorption capacities of the four bentonite samples used were found to be 8.41, 12.24, 21.79, and 21.93 mg g-1, respectively. The results best fitted the pseudo-second-order kinetic model, with constant rates in a range of 0.0948-0.3153 g mg-1 min. The effect of temperature was investigated at temperatures of 20, 30, and 40 °C. Thermodynamic parameters, including standard enthalpy (?H0), Gibbs energy (?G0), and standard entropy (?S0), were calculated. The adsorption of Ni(II) by bentonite samples was an endothermic and spontaneous process. These results indicated that, of the bentonite samples used, the natural bentonites from JP and SK were most suitable for the removal of nickel from synthetically prepared solutions.
| S-EPMC7827643 | biostudies-literature
Project description:A Novel approach to remove metals from aqueous solutions has been developed. The method is based on a resin free, solid, non-toxic, microcrystalline bisphosphonate material, which has very low solubility in water (59?mg/l to ion free Milli-Q water and 13?mg/l to 3.5% NaCl solution). The material has been produced almost quantitatively on a 1?kg scale (it has been prepared also on a pilot scale, ca. 7?kg) and tested successfully for its ability to collect metal cations from different sources, such as ground water and mining process waters. Not only was this material highly efficient at collecting several metal ions out of solution it also proved to be regenerable and reusable over a number of adsorption/desorption, which is crucial for environmental friendliness. This material has several advantages compared to the currently used approaches, such as no need for any precipitation step.
| S-EPMC4355739 | biostudies-literature