Frendlich Isotherm Research Articles

Thin-Film Nanocomposite Membranes of Cellulose Nanocrystal/Silver (CNC/Ag) for Removal of Phenol Compounds

Bagasse is the sugar cane residue obtained from the sugar industry. It is produced in large quantities and used to make paper because of its fibrous structure. In the present research, sugarcane bagasse (SCB) was chemically treated with HNO3, NaOH, and a bleaching agent to recover 58% of the chemically purified cellulose (CPC), which was subsequently hydrolyzed with H2SO4 to form cellulose nanocrystal (CNC). The capacity of a composite membrane made of cellulose nanocrystal (CNC) enhanced with silver nanoparticles (Ag NPs) to extract phenols from petrochemical effluent was examined. The prepared membrane was examined using a scanning electron microscope (SEM), transmission electron microscopy (TEM), and X-ray diffraction (XRD). The results showed that the white spot on the crystal surface suggested AgNP agglomeration on the CNC surface. The nanocellulose possessed crystallinity indices ranging from 21.9 to 33.1 nm, whereas the silver particles measured 23 and 62 nm. The high separation result of phenol obtained at casting composition of 14% Ag NPs reached 60% at an equilibrium time of 45 min and pH 9. The isothermal and kinetic analysis explained that the rate of adsorption process is the pseudo-second order and followed the Frendlich isotherm models. The CNCs generated using this approach were found to be less agglomerated and more crystalline, indicating a better potential as bio-nanocomposite materials for wastewater treatment.

Cost-effective synthesis of magnetic graphene oxide nanocomposite from waste battery for the removal of arsenic from aqueous solutions: Adsorption mechanism with DFT calculation

In this study, magnetic graphene oxide (MGO-Fe3O4) nanocomposite was prepared by co-precipitating of FeCl3.6H2O and FeCl2.4H2O on waste battery-derived graphene oxide and used as an adsorbent for the efficient removal of As(III) from aqueous solutions. The prepared nanocomposite was characterized by Fourier transformed infrared spectroscopy, field emission scanning electron microscopy, transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, zeta potential, and a vibrating sample magnetometer. These characterizations revealed that spare like Fe3O4 nanoparticles (10.5 nm) were decorated on graphene oxide nanosheets and showed excellent saturation magnetization (89.73 emu/g). The adsorption of As(III) by MGO-Fe3O4 was optimized by analyzing various parameters. Experiments showed that 98 % of As(III) was removed at neutral pH in a just 20 min, even though the adsorbent dose was only 0.14 g/L. The adsorption kinetic and isotherm were best fitted with the pseudo-second order kinetic and Frendlich isotherm model. The maximum adsorption capacity (qmax) was found to be 50.2 mg/g at room temperature. Thermodynamic studies showed that the As(III) adsorption process was spontaneous and exothermic in nature. The enhanced adsorption capacity and magnetic properties of MGO-Fe3O4 are crucial in the drinking water treatment process due to the easy magnetic separation of MGO-Fe3O4 from aqueous solution after the adsorption process. Density Functional Theory (DFT) was also used to investigate the interaction between MGO-Fe3O4 and As(III), which further suggested that MGO-Fe3O4 and As(III) mostly interact with each other through surface complexation and hydrogen bonding.

INVESTIGATION OF THE PHOSPHATE IONS ADSORPTION FROM ALUMINATE SOLUTIONS BY Fe-AС NANOCOMPOSITE

The adsorption of phosphate ions from model solutions by a nanocomposite based on trivalent iron oxide-hydroxide and activated carbon (Fe-AС) was studied. Factors studied affecting the adsorption of phosphate ions: solution pH; adsorbent amount; initial concentration of phosphate ions in solution; contact duration. The efficiency of phosphate ion extraction increased with increasing adsorbent dosage (from 2.5 to 10 g/l) with an initial concentration of phosphate ions of 0.1 g/l. Adsorption is well described by the Langmuir and Frendlich isotherms. The results of the work showed that the Fe-AС nanocomposite has a good potential for adsorption of phosphate ions from aluminate solutions, which was confirmed by SEM/EDS analysis.

A REVIEW ON: REMOVAL OF LEAD FROM WASTE WATER BY VARIOUS TECHNIQUES AND METHODS

Lead is one of the most dangerous compounds present on earth. The presence of this particular compound in waste water causes toxicity to environment and also to human beings. Various methods has been analysis on different ways to carry out the lead content from water like the use of activated charcoal, some natural and synthetic adsorbents, extraction from waste water ,ion exchange, various precipitation techniques has been analysed for removal of lead. There are few models like Langmuir and frend lich isotherm are used in these methods for removal of lead. The removal of lead is found to be a sum of adsorption induced by ion exchange and precipitation of lead hydroxide. The main sources of the lead are these heavy industries, smoke from transportation both by natural and manmade activities are responsible. The various parameters that affect these methods are the pH concentration, time contact and metal ion concentration, and also its adsorption capacity. This review article presents the information about the removal of lead (Pb) and (Pb+2) ions from various techniques and models from waste water.

Evaluation of Langmuir and Frendlich isotherm equation for Zinc Adsorption in some calcareous soil of Erbil province north of Iraq.

The purpose of this study soil samples were to investigate of Zinc concentrations on the mechanism of adsorption phenomena in four calcareous soils (Choman, Qoshtepe, Herir, and Soran) from Erbil North Iraq classified (calciorthids). Isotherm adsorption was studied by using the Batch technique, 2 g soil was shaken with 40 ml 0.01M CaCl2 containing Zn concentrations of 0, 1, 2, 4, 8, 16, 32, 64, 128, and 256 mg Zn l-1 for 24 hours at 298K. Zn adsorption under isotherm reaction 298K. The adsorption data were described by using Langmuir and Freundlich equations. The results showed that the concentration of adsorption was increased by an increase of Zn level added to Soils. According to the Langmuir equation, the maximum adsorption capacity of Zn was higher in Qoshtepe, Herir Soils. 666 mg kg−1 while the lower value was recorded in Soran soil. Bonding energy was higher in Soran 0.4050 mg L−1, while the lower value was recorded in Choman Soils. 0.0184 mg L-1 soil MBC was higher in Soran Soil. 134.87 mg kg−1 while the lower value was recorded in Choman 7.65 soil, also the results showed that reaction was spontaneous with Negative free energy, were higher in Soil. -2.16 while the lower value was recorded in Herir soil -1.94 joule.mole−1.degree-1 for Soil. And RL value was higher in Choman Soil 0.71, while the lower value was recorded in Soran soil 0.32. The values of qm constant Dubinin-Radushkevich (D-R isotherm) which is the adsorption capacity mol g−1 ranged from -2.3007 to -3.6758

Investigation of the adsorption performance of acid treated lignite coal for Cr (VI) removal from aqueous solution

Several methods have been used to reduce the negative contribution of heavy metal contaminants effluents in the environment. The method studied in this research was the use of activated carbon derived from Ethiopian lignite for hexavalent chromium adsorption from aqueous solution. The adsorption study was evaluated as the function of initial Cr (VI) concentration, adsorbent dosage and pH. All the batches' tests were conducted by using synthetic wastewater in this study. General Factorial Design (GFD) of Response surface methodology (RSM) was used in this batch test for analysis of experimental. The effects of independent variables on various initial Cr (VI) concentrations between 20 ppm and 100 ppm were evaluated. According to ANOVA analysis, each and combined term is statistically significant. A Cr (VI) removal efficiency of 98 % was achieved at pH 1 with 3.5 g of LAC in 200 ml of solution at 4 h of contact time using initial Cr (VI) concentration of 20 ppm. Removal increased up to 96.54% when Cr (VI) concentration decreased to 20.5 ppm, and adsorbent dose increased to 3.01 g at pH 1. 49.94% chrome removal was achieved at Cr (VI) concentration of 100 ppm and pH 5 with an adsorbent dose of 3.5 g for the combined effect of initial Cr (VI) concentration and pH, which was decreased with increased both initial Cr (VI) concentrations and pH value. With the combined effect of pH and adsorbent dosage the maximum percentage removal of Cr (VI) ion was obtained at lower pH and higher adsorbent dosage (96.5%). The adsorption of Cr (VI) was evaluated using batch adsorption equilibrium isotherms (Langmuir and Frendlich) and kinetics reaction rate (first and second order). The Frendlich isotherm model was the best one for the description of adsorption of Cr (VI) onto LAC heterogeneous surface energy. The adsorption kinetics of Cr (VI) onto LAC followed the second order kinetic model, suggesting that the adsorption reaction rate depends on two parameters, which might be the Cr (VI) concentration and adsorbent dosage. These results support similar conclusions mentioned by several authors in the literature.

Mitigation of Cu(II) from Aqueous Solution by Using Sandal Santalum Album Distillation Biomass

In this study, mitigation of Cu(II) from aqueous solutions was evaluated using the sandal Santalum Album as biosorbent. The removal capacity of the Cu(II) was studied in batch experiments including such as initial metal concentration (25-400 mg/L), biosorbent dose (0.05-0.2 g), effects of contact time (0-1440 min), kinetics and pre-treatment of the biosorbent. The maximum removal of Cu(II) was obtained at the optimum pH of 5. The maximum equilibrium uptake for Cu(II) was Ba(OH)2-SA(248.8 mg/g-1) at 400 ppm. Kinetics studies explained that, mitigation of the Cu(II) was very fast from 0 to 120 min and achieved equilibrium at 240 min. The equilibrium was well explained by Frendlich isotherm. Kinetics was well fitted to pseudo second order equation with high R2 values.

Facile preparation of biosurfactant-functionalized Ti2CTX MXene nanosheets with an enhanced adsorption performance for Pb(II) ions

The aim of this study is to improve the adsorption performance for Pb(II) ions of a novel two-dimensional Ti2CTX MXene. Three biosurfactants, chitosan (CS, a cationic surfactant), lignosulfonate (LS, an anionic surfactant) and enzymatic hydrolysis lignin (EHL, a non-ionic surfactant), were used to functionalize the Ti2CTX nanosheets. The samples were characterized by using Field-emission scanning electron microscopy, Fourier infrared spectroscopy, X-ray diffraction and Nitrogen adsorption-desorption isotherms, their adsorption performances for Pb(II) ions were investigated by bath adsorption experiments under various adsorption conditions including different types of biosurfactants, pH value, initial Pb(II) ions concentration, adsorbent concentration, contact time and adsorption temperature. Results revealed that the non-ionic surfactant EHL prevents Ti2CTX nanosheets from restacking and introduces active functional groups so that the adsorption performances of the EHL-functionalized Ti2CTX nanosheets are promoted. The EHL-functionalized Ti2CTX displayed a maximum adsorption capacity of 232.9 mg g−1 for Pb(II) ions. Moreover, reaction kinetics, isotherms and thermodynamics studies were analyzed to describe the adsorption behaviors, and the experimental data were fitted well with pseudo-second order model and Frendlich isotherm. The results showed that the biosurfactants-functionalized Ti2CTX shows improved adsorption performances in removal of Pb(II) ions and has great potential as an environmental adsorption material.

Molecular weight-dependent adsorption fractionation of natural organic matter on ferrihydrite colloids in aquatic environment

Natural organic matter (NOM), a heterogeneous mixture with various organic components and continuous molecular weight (MW) distribution, is omnipresent in natural waters. To date, understanding of the MW-dependent adsorption fractionation of NOM samples on colloids is limited due to the lack of NOM fractionation and characterization methods. In this study, the ultrafiltration technique was applied to fractionate the bulk NOM samples into low MW (LMW-, <1 kDa) and high MW (HMW-, 1 kDa–0.45 μm) fractions, whose adsorption behaviors on ferrihydrite colloids were comparatively examined via using total organic carbon, chromophoric, fluorescent emission-excitation matrix-parallel factor (EEM–PARAFAC), and two dimension FTIR correlation spectroscopy (2D–FITR–COS). The adsorption behaviors of all samples can be reasonably explained by Langmuir and Frendlich isotherm models, and the HMW-NOM exhibited higher adsorption capacities and affinities (4.71 mg-C/g) than the bulk (3.88 mg-C/g) and LMW- (2.44 mg-C/g) counterparts. Irrespective of MWs, the non-aromatic moieties were preferentially adsorbed by ferrihydrites, causing an enhanced aromaticity for the residual solutions. Two humic-like and one protein-like component were identified by EEM–PARAFAC, and a increase and decrease trend of Ka (adsorption affinity) were observed for humic- and protein-like components, respectively, in the order of LMW-, bulk, and HMW-NOM, showing obvious MW- and component-dependent adsorption fractionation of NOM on ferrihydrite colloids. 2D–FTIR–COS provided further information that, with increasing site limitation, the C–O in carbohydrate was adsorbed prior to the amide I in proteins, which testified the MW-dependent adsorption fractionation of NOM samples and accounted for the enhanced aromaticity in the residual solutions. This study highlighted the importance of MWs in NOM adsorption, which can enhance our understanding of the biogeochemical cycles of colloids and contaminants in aquatic environments.

Preparation of novel oxidized mesoporous carbon with excellent adsorption performance for removal of malachite green and lead ion

An oxidized mesoporous carbon (OMC) with fluffy structure was fabricated from the mixture of petroleum asphalt and aluminum isopropoxide, and its structures were characterized by FESEM, TEM, BET, TG, XPS and FT-IR. In addition, bath absorption experiments for malachite green (MG) and lead ion (Pb2+) were carried out to explore the effects of pH, initial concentration, contact time and temperature on its absorption process. Results show that the OMC prepared has a fluffy ultrathin-wall structure with narrow pore size distribution and rich oxygen-containing groups. It exhibits excellent absorption performance for the removal of MG as well as Pb2+, as indicated by that its maximum adsorption capacity is 963.1 mg g−1 for MG and 198.6 mg g−1 for Pb2+. The absorption experimental data are all fitted well with pseudo-second-order model and Frendlich isotherm, respectively. More importantly, the OMC still maintains relatively high adsorption capacity after five cycles.

Biosorption of Lead (II) onto soda lignin gels extracted from Nypa fruiticans

Lignin is relatively abundant in nature but its utilization potentials as an adsorbent for the removal of metals from waste water have not been fully exploited. Biosorption experiments were carried out for the removal of Pb+2 from aqueous solution, using novel lignin gels (soda lignin and sulfonated resinified soda lignin) extracted from Nypa fruitcans. The effects of major variables governing the efficiency of the process such as pH, adsorbent dosage, contact time, initial concentration and temperature were studied by the batch process. Equilibrium data was fitted into the Langmuir and Frendlich isotherm models. Adsorption kinetics was analyzed using the pseudo- first and second- order models while thermodynamic parameters such as ΔH, ΔS and ΔG were estimated accordingly. The results showed that the sorption process was best represented by the Langmuir isotherm while the pseudo- second- order model was the appropriate model describing the adsorption kinetics. The optimum adsorption occur at pH of 4 and 6, corresponding to a maximum adsorption of 94.24 and 96.34% for the unmodified lignin (UL), and sulfonated resinified lignin (SRL), respectively. The adsorption process was found to be endothermic and spontaneous. An indication of kinetic performance (Rw), suggests that sulfonated lignin approaches equilibrium faster and would likely remove more Pb+2 from solution than the unmodified lignin. Similarly, optimization of the biosorbent dosage in a single stage batch design revealed that more than twice, the amount of SRL biosorbent is required by the UL to remove over 94% of lead (II) ions from aqueous solution.

Fouling Behavior of Negatively Charged Natural Organic Matters to Anion Exchange Membranes in Reverse Electrodialysis

Reverse electrodialysis (RED) represents an energy conversion technology from the salinity difference of concentrated salt solutions (e.g., sea water) and diluted salt solutions (e.g., river water). The RED stack is comprised of an alternating arrangement of cation- and anion-exchange membranes between two electrodes that selectively transfer anions and cations. However, the river water used for the RED may contain natural organic matters (i.e., humic acid and fulvic acid). Thus, electrostatic characteristics of organic matter may lead to membrane surface fouling. The membrane fouling cause increase electrical resistance and the increase of maintenance cost, and a significant decrease in operating performance. In this study, the influence of membrane fouling in RED by commercially available humic acid was investigated experimentally, and adsorption tests, open circuit voltage, stack resistance, and power density were measured at different operation conditions. As a result, it was confirmed that the adsorption of humic acid onto the surface of anion-exchange membranes occurred even though the direction of the electromigration of negatively charged humic acid was toward cation-exchange membranes. The fouling of anion exchange membranes by humic acid was highly influenced by the roughness of the surface of anion-exchange membranes. It was confirmed by isothermal curves (i.e., Frendlich isotherm). Acknowledgements This work was supported by the New and Renewable Energy of the Korea Institute of Energy Technology Evaluation and Planning (KETEP) granted financial resource from the Ministry of Trade, Industry & Energy, and Republic of Korea (No. 20143030071240).

Material prepared from drinking waterworks sludge as adsorbent for ammonium removal from wastewater

Drinking waterworks sludge (DWS) is not an effective adsorbent for ammonium removal without any treatment. In this study, DWS was used as a starting material to prepare ammonium adsorbent (M-DWS) by means of an ultrasonic assisted extraction and synthesis method. Two materials (M-DWS1# and M-DWS2#) were prepared according to two different routes. The composition, structure, and surface properties of DWS and M-DWS were characterized and their ammonium adsorption abilities were examined. Characterization results showed that the lamellar structure of DWS was converted into the spherical units of M-DWS and that the cation exchange capacity and specific surface area of M-DWS were many times higher than that of DWS. Batch test results indicated that the adsorption equilibrium data of M-DWS fitted well to both the Langmuir and Frendlich isotherms. The maximum adsorption capacity of M-DWS1# and M-DWS2# evaluated from the Langmuir isotherm was 6.11mg/g and 5.10mg/g, respectively. It was also observed that the initial pH affected ammonium adsorption on M-DWS greatly. Under an optimum pH of 7–8, the highest ammonium removal rate of 90% for M-DWS1# and 80% for M-DWS2# were achieved at an initial concentration of 50mg NH4+/L. The advantage of M-DWS2# lies in its higher yield and less waste discharge compared with M-DWS1#.

Interaction between Kaolin and Urea in Organoclay and Its Impact on Removing Methylene Blue from Aqueous Solution

Interaction between kaolin (particle size 53 and 106 μm) and urea was studied by infrared spectroscopy and powder X-ray diffraction. Interaction was found to be dependent on the particle size of kaolin raw material. Nature of interaction achieved through the formation of hydrogen bonds between urea and both AlOH and Si-O surface of kaolinite. Effect of temperature on equilibrium adsorption of methylene blue (MB) from aqueous solution using kaolin also studied, the results were analyzed by Langmuir and frendlich isotherms. Thermodynamic parameters such as ΔG, ΔH and ΔS were calculated. Results suggested that the MB adsorption on kaolin was spontaneous and exothermic process.

Statistical investigation of lead removal with various functionalized carboxylate ferroxane nanoparticles

Four new types of carboxylate-ferroxane nanoparticles, namely; maleate ferroxane (MF), fumarateferroxane (FF), para-amino benzoate ferroxane (PABF) and para-hydroxy benzoate ferroxane (PHBF) were synthesized, characterized and used for lead removal from aqueous solutions. Lepidocrocite nanoparticles were also synthesized and characterized asa precursorforcarboxylate-ferroxanes. FTIR, SEM and DLS analysis characterized the synthesized samplesand final Pb(II) concentration were analysed using inductively coupled plasma atomic emission spectrometer. Performance evaluation of the nanoparticlesin adsorption process was achieved using Taguchi experimental design. Variables in adsorption process were initial pH, contact time, adsorbent dose, adsorbent typeand initial concentration of Pb2+ ions. The initial Pb(II) concentration was the most influential factor in the adsorption process among the five factors. Adsorption of lead was performed through two possible mechanisms; ion exchange and complex formation. Maleate ferroxane performed the best lead removal efficiency among the four types of ferroxane nanostructures studied. The adsorption kinetic data described well with a pseudo-second-order model and the equilibrium data fitted well to the Frendlich isotherm.

Interaction between Kaolin and Urea (organoclay) (FTIR, XRD and thermodynamic studies)

Interaction between kaolin ( particle size 53 and 106 μm ) and urea was studied by infrared spectroscopy and powder X-ray diffraction. Interaction was found to be dependent on the particle size of kaolin raw material. Nature of interaction achieved through the formation of hydrogen bonds between urea and both AlOH and Si – O surface of kaolinite. Effect of temperature on equilibrium adsorption of methylene blue ( MB ) from aqueous solution using kaolin also studied, the results were analyzed by Langmuir and frendlich isotherms. Thermodynamic parameters such as ΔG, ΔH and ΔS were calculated. Results suggested that the MB adsorption on kaolin was spontaneous and exothermic process.

Characterization and Adsorption Mechanism of Pb (II) Removal by Insolubilized Humic Acid in Polluted Water

The removal of Pb2+ in the aqueous solutions by adsorption onto insolubilized humic acid (IHA) is investigated. The equilibrium isotherms were determined at pH 3.5 under constant ionic strength and at different temperatures. At the same time, the paper has also analyzed the adsorption experimental data by using three different isotherm models: Langmuir, Frendlich and Linear isotherm. As the result, it has obtained the optimal correlation for Frendlich isotherm equations. In addition, the paper has calculated the thermodynamic quantities ΔH in accordance with the Clausius-Claperyon,s theory. It means that the type of adsorption of Pb2+ onto IHA is physisorption, rather than by chemical bonding. And finally, the adsorption equilibrium gained around 12 hours and a high and stable removal of heavy metals on insoluble humic acid has been obtained almost under the neutral conditions.

MEASUREMENTS OF MINERAL WATERS POLLUTION IN ADSORPTION THERMODYNAMIC STUDY 0F BERLENT GREEN DYE ON SURFACE BENTONITE CLAY

It was found in this research that the mineral waters contain high concentrations of TDS which was confirmed by high values of their conductivities which were directly proportional to their TDS. The levels of TDS in Found waters were not controlled in time of preparation of these waters. The adsorption of Berlent Green dye on Bentonite Clay surface decreased with increasing temperature which was confirmed by negative values of enthalpies and free energies in addition to negative valves of entropies which rendered the system most regulation. The adsorption follows Frendlich isotherm and the adsorption increased with decreasing pH which reached its maximum value at pH=1.There fore, these waters should be defected from time to insure their suitability for drinking and their contents within the water Health Organization specifications and using(U.V-visible) Instrument, (pH-meter) for measurements.

Removal of methylene blue using acid and heat treatment of clinoptilolite

The adsorption of methylene blue from aqueous solution onto clinoptilolite has been studied under various experimental conditions. Heat treatment and acid treatment have also been applied to modify the clinoptilolite. It is found that heat treatment and acid treatment can significantly change the adsorption capacity. The treatment of clinoplites has the higher adsorption capacity than untreated ones. The adsorption data have been analyzed using Langmuir and Frendlich isotherms. The results indicate that the Langmuir model provides the better correlation of the experimental data. Isotherms have also been used to obtain the thermodynamic parameters such as free energy, enthalpy and entropy of adsorption. For heat treatment of clinoptilolite, adsorption of methylene blue is endothermic reaction with ΔH ads at 50.67 kJ/mol.

Biosorption of copper from wastewater by activated carbon preparation from alga Sargassum sp.

In this study, the batch removal of copper(II) ions from an aqueous solution and wastewater using marine brown alga Sargassum sp. was investigated. Activated carbon prepared from Sargassum sp. by acid decomposition was also used for the removal of copper from the aqueous solution and wastewater. Activated carbon-prepared marine algae were used as a low-cost sorbent. The effect of pH, biosorption time, adsorbent dose and metal ion concentration were considered. The most effective pH was found to be 4.0. The biosorption capacities were pH dependent on the solution and the maximum uptake for copper with initial concentrations of 70, 100 and 150 mg L−1 at pH 4.0 were obtained as 95.68, 95.09 and 94.83%, respectively. Total metal ion biosorption occurs within 2 h. The equilibrium adsorption data are fitted to Lomgmuir and Frendlich isotherm models. Both models represent the experimental data satisfactorily. The adsorption follows second-order kinetics. This study shows that the use of activated carbon is a valuable material for the removal of copper from aqueous solutions and wastewater, and a better substitute for use in activated marine brown algae.