Freundlich Isotherm Equation Research Articles

Optimizing modified rice bran for treating aqueous solutions polluted by Cr (VI) ions: isotherm and kinetics analyses

This study investigated the possibility and efficiency of absorbing chromium (VI) (Cr [VI]) ions from the polluted solutions by employing the chemically modified adsorbents (alkali, biochar, and acid rice bran), focusing on the possible impacts of the solution’s pH values, adsorbent’s dosages, concentrations, and contact times. The colori-metric method was used for Cr determination by employing an ultraviolet/visible spectrophotometer. The scanning electron microscope and Fourier transform infrared spectroscopy were used to analyze the characteristics of the modified adsorbents. The findings indicated that the optimized acid, biochar, alkali, and unmodified rice bran removal efficiency for Cr (VI) were 94.50%, 94.27%, 88.60%, and 90.18%, respectively. The increase of adsorbent dosage up to 2 g/L led to a rise in removal effectiveness (82.06%). Furthermore, the highest removal efficiency was obtained (94%) at the pH of 2.0, the contact duration of 100 min, Cr (VI) concentration of 50 mg/L, and dosage of 2 g/L, which was statistically the optimal condition for the modified rice bran. The adsorption kinetics was agreeably suited to pseudo-second-order, whereas the Freundlich isotherm equation was also suitably expounded the study’s findings. The findings implied that the acid and biochar rice bran performed remarkably in the reme-diation of the wastewater compared with alkali rice bran for reuse for industrial, agricultural, and environmental purposes.

A facile synthesis of hyper-cross-linked polystyrene resins for phenol removal

Hyper-cross-linked polystyrene networks (HPNs) were obtained from macroporous slightly cross-linked polystyrene by using inexpensive and commercial dichloroalkanes as external cross-linkers via a two-step Friedel-Crafts reaction. In this reaction, AlCl3 or FeCl3 was used as catalyst, and the highest Brunauer-Emmett-Teller (BET) surface area (SBET) of the HPNs was amounted to 832.8 m2/g using a starting polymer with a SBET of 19.5 m2/g. The results showed that physical properties such as surface area and swelling behaviors of the HPNs could be regulated by varying the strut length and structure of cross-linkers. The sorption performance of the HPNs for phenol was greatly improved due to both adsorption on the surface and absorption in the matrix through framework swelling. The equilibrium adsorption capacity of phenol on HPN-DCM-DCE reached 24.5 mg/g and 170.0 mg/g at the equilibrium concentration of 2 mg/L and 200 mg/L, respectively. The equilibrium isotherm and sorption kinetic studies indicated that the sorption behaviors could be well fitted with Freundlich isotherm equation and the pseudo-second-order rate equation.

Kinetics, isotherm and thermodynamic studies of S2− adsorption by (SBA-15)-Hg (II)

Abstract The nano-mesoporous material SBA (Santa Barbara Amorphous)-15 was synthesized using the hydrothermal method. Hg2+ was adsorbed by SBA-15 and then the S2− in the aqueous phase by (SBA-15)-Hg(II), with the hope that materials with better S2− adsorption properties can be obtained. The relevant materials were characterized by X-ray diffraction, scanning electron microscopy, 77 K nitrogen adsorption-desorption, and related product characteristics were determined. In this work, the adsorption conditions of S2− onto (SBA-15)-Hg(II) were optimized. Adsorption efficiency reached about 92% and the adsorption capacity 55.02 mg/g. Studies of the system's adsorption kinetics showed that the pseudo-second-order equation applies. The thermodynamic results indicated that ΔG0 < 0, ΔH0 = −28.56 kJ/mol, ΔS0 = −81.136 J/(mol·K), and that adsorption is exothermic, enthalpy decreases and the reaction is spontaneous. This accords with the Freundlich isothermal adsorption equation.

Swelling Behaviour of Starch-g-Acrylic Acid Hydrogel and its Potential Application in Removal of Rhodamine B and Alkali Blue Dyes

Starch-g-acrylic acid hydrogel was prepared by free radical polymerization technique adopting potassium persulphate (KPS) as an initiator and N’N-methylenebisacrylamide (MBA) as a linking agent. The aim of the research is to inspect the potentials of starch-based hydrogel in remediating wastewater. Fourier Transform Infrared (FT-IR) spectroscopy was used to find the formation of hydrogel while Differential Scanning Calorimetry (DSC) and Scanning Electron Microscopy (SEM) were used for the characterization of the hydrogel. The FT-IR spectroscopy confirmed hydrogel formation. The DSC results showed that the generated hydrogel is thermally stable, and the SEM depicts a good porous site for dye adsorption. Batch adsorption for Rhodamine B (RDB) and Alkali blue (AB) dyes under the variation of contact time was 105 minutes for both dyes with percentage removal of 89.80 and 60.32%, adsorbent dose was 0.4 and 0.8 g with percentage removal of 86.42 and 57.95%, concentration was 50 and 30 ppm with percentage removal of 67.01 and 77.18% and pH was 8 for both dyes with percentage removal of 77.43 and 79.13% as the optimum. The results indicates that acrylic acid monomer was efficiently grafted on the starch, and the adsorption method correlated with Freundlich isotherm equation. It was concluded that the starch-based hydrogel is an appropriate adsorbent and can be explored for industrial wastewater treatment.

Mesoporous activated carbon as a green adsorbent for the removal of heavy metals and Congo red: Characterization, adsorption kinetics, and isotherm studies

In this study, an effective and green adsorbent was prepared by the self- activation of kenaf fiber and then the kenaf-based activated carbon (KAC) was applied for the removal of lead Pb(II), copper Cu(II), and Congo red (CR) dye from an aqueous solution by the process of adsorption. The surface morphology of mesoporous adsorbent was characterized. The KAC showed good capacity of adsorption of as Pb(II), Cu(II), and anionic dye CR in very short period of agitation. The adsorbent efficiency of metal ions and dye was estimated by varying the adsorbent dose, pH, contact time, initial metals and dye concentration, and temperature. Optimum adsorption of metal ions and CR dye was observed at pH 6, and at pH 4 at 120 min, respectively. The adsorption isotherm was described by the Langmuir and Freundlich isotherm equations. The green adsorbent followed the pseudo-second-order kinetic model with correlation coefficients R2 value >0.99. The increase in adsorption temperature enhanced the adsorption efficiency for both heavy metals and dye. The KAC showed no significant loss of the adsorption capacity after 3 cycles of reuse.

Amidinothiourea‐linked covalent organic framework for the adsorption of heavy metal ions

AbstractFor the first time, a novel amidinothiourea‐linked covalent organic framework (COF) (TpAt) has been successfully synthesized by the condensation between 1,3,5‐triformylphloroglucinol and amidinothiourea via vacuum solvothermal reaction, and was further utilized for the adsorption of metal ions from aqueous solution. The effects of initial concentration, pH and contact time on the adsorption process were investigated. As a result, the TpAt COF showed maximum binding capacities as high as 95.44, 100.76 and 99.08 mg g–1 for Cr(III), Cd(II) and Cu(II) within 180 min at the initial concentration of 100 mg L–1, respectively. The isotherms of metal ions onto TpAt could be described by the Freundlich isotherm equation, and the adsorption kinetics followed the pseudo‐second‐order model. The TpAt could be reused for more than five adsorption–elution cycles, whilst basically maintaining its original adsorption performance and the structural integrity of the COF layers. The robust adsorption efficiency can be attributed to the coordination between metal ions and N, O and S atoms in the TpAt framework. The TpAt COF represents an ideal candidate for the removal of heavy metal ions in environmental pollution treatment. © 2021 Society of Industrial Chemistry.

Tailored metal-organic frameworks facilitate the simultaneously high-efficient sorption of UO22+ and ReO4− in water

The simultaneously efficient extraction of radioactive metal cations and anions from radioactive waste is of great interest for the proper disposal of spent fuel and environmental protection. Modifying metal-organic frameworks (MOFs) into multifunctional materials with controllable and desired properties is an efficient strategy for broadening their practical applications. Herein, poly(ethyleneimine) (PEI) tailored MIL-101(Cr) (MILP) was obtained through an easy operation and low-cost strategy and was utilized to simultaneously extract uranium (UO22+) and rhenium (ReO4−) from water. The effects of PEI coating amounts, system pH, contact time, initial UO22+/ReO4− concentrations, ionic strength, as well as interfering ions were studied to evaluate the sorption performance of MILP composites. The maximum sorption capacity was 416.67 mg/g for UO22+ at pH 5.5 and 434.78 mg/g for ReO4− at pH 3.5, levels that are superior to those of most adsorbents. The sorption of UO22+/ReO4− occurred in a pH-dependent, spontaneous and endothermic manner, which showed preferable modeling by the pseudo-second-order (PSO) kinetic equation and Freundlich isotherm equation. The adsorption of ReO4− was inhibited by the coexistence of UO22+ and high ion strength. Batch experiments and X-ray photoelectron spectroscopy (XPS) results indicate that UO22+/ReO4− sorption was driven by the abundant amino groups and unsaturated metal sites in the MILP-3 composites. MILP-3 also showed excellent recycling performance and maintained high sorption capacities for UO22+/ReO4− in different simulated water samples. This study shows that MILP composites can effectively extract radioactive metal cations and anions from water, and lays a foundation for designing an excellent new category of candidates with versatile functions for wastewater management.

Effects of soil depth and characteristics on phosphorus adsorption isotherms of different land utilization types: Phosphorus adsorption isotherms of soil

Phosphorus (P) is an indispensable natural mineral for biological processes and structures that support life in plants and animals. P deficiency is the most common nutritional stress of cultivated land in many regions of the world. The aim of this study was to determine the phosphorus (P) sorption characteristics of some soils and derive parameter estimates relevant in the prediction and management of P as well as their relationship to the properties of the soils. Four soil samples (each taken from depths of 0−10, 10−20 and 20−30 cm) were obtained from the Eastern Region of Ghana for this study. An uncultivated virgin land at Huhunya (HV), a cocoa farm in Akwadum (AC), a plantain farm also in Huhunya (HP) and piece of land which had been allowed to go fallow in Huhunya (HF) was used. Measurement of P sorption was conducted by equilibrating air-dried soil (<2 mm) in 0.2 M CaCl2 solution containing various concentrations of P. Phosphorus sorption data for soils was fitted to the Langmuir, Freundlich and Temkin isotherm equations. The result of the study show that the amount of phosphorus adsorbed increased with increasing depth with AC soil recording an average range of 114.16−211.55 μg/g. Phosphate adsorption was well described by the three isotherm equations. The data from the soils did conform best to the Langmuir equation with an average r2 value of 0.99. It was realized that virgin soil (from Huhunya) would require the most P fertilizer. The least P fertilizer would be required by the soil from the plantain farm (HP). Correlation analysis showed a significant relationship between some soil characteristics and the sorption parameters derived from the three equations.

Preparation of a bacterial flocculant by using caprolactam as a sole substrate and its application in amoxicillin removal

High cost is one of the limiting factors in the industrial production of bioflocculant. Simultaneous preparation of bioflocculant from the contaminants in wastewater was considered as a potential approach to reduce the production cost. In this study, caprolactam was verified as sole feedstock for the growth of strain Alcaligenes faecalis subsp. phenolicus ZY-16 in batch experiments. Chemical analysis showed that the as-prepared MBF-16 consisted of heteropolysaccharides (88.3%) and peptides (9.4%). XPS result indicated the plentiful acylamino, hydroxyl and amino groups in MBF-16, which have an indispensable role in amoxicillin flocculation. The flocculation of amoxicillin can be well stimulated by Freundlich isotherm equation, and the Kf was up to 178.6524 for amoxicillin. The kinetic fitting results proved that the flocculation of amoxicillin by MBF-16 was chemisorbed. This contribution may develop a novel technology for the preparation of bacterial flocculants that can consume toxic substrates (caprolactam) and have potential applications in amoxicillin removal.

High efficient Hg (II) and TNP removal by NH2 grafted magnetic graphene oxide synthesized from Typha latifolia

ABSTRACT The present study for the first time manifests the outstanding potential of amine grafted magnetic graphene oxide (m-GO-NH2) synthesized from Typha latifolia stems for mercury (Hg (II)) and 2,4,6-trinitrophenol (TNP) removal. The adsorption performance of m-GO-NH2 was apprized by considering the impact of the contact time (0–120 min), pH (2–9), adsorbent dose (5–40 mg), and adsorbate concentration (10–50 mg/L). The maximum Hg (II) and TNP removals (∼ 100%) were obtained using 30 mg adsorbent dose in 90 and 75 min, respectively. The best performance of m-GO-NH2 was observed at pH of 7, 20 mg/L Hg (II), and pH of 2, 30 mg/L TNP. According to the Brunauer–Emmett–Teller (BET) analysis, the surface area of GO was 34.81 m2/g and the simultaneous micro and mesoporosity was observed. Regarding the thermodynamic studies, the adsorption procedure was spontaneous and endothermic for Hg (II) followed Redlich-Peterson (R-P) and Freundlich isotherm equations while it was exothermic for TNP, well fitted with Langmuir and R-P isotherms. Kinetic data also indicated a good correlation with pseudo-second-order model. The highest adsorption capacity was estimated as 107.33 and 105.2 mg/g for Hg (II) and TNP, respectively. Accordingly, the proposed m-GO-NH2 can be a promising adsorbent for the elimination of metal and organic contaminants.

OPTIMIZATION OF RHODAMINE-B DYE SORPTION POTENTIAL FROM AQUEOUS SOLUTION USING ACTIVATED CARBON DEVELOPED FROM THE AERIAL ROOT OF FICUS BENGHALENSIS L

Adsorptive interaction of Rhodamine-B dye onto microwave assisted zinc chloride activated carbon from aqueous solution was investigated. Activated carbon was prepared from the aerial root of Ficus benghalensis L. Carbon prepared was designated as ZAC (zinc chloride activated carbon). Experiments were carried out in a batch process using various parameters such as pH, dose of the adsorbent, contact time, initial dye concentration. Kinetics of the system were studied with linearised forms of Lagergren, HO and Webber Morris model. Equilibrium data were showed with Langmuir, Freundlich, Tempkin, and Dubinin-Raduskevich isotherm equations. Implications obtained from the isotherm parameters were discussed. Thermodynamic parameters such as ΔH°, ΔS° and ΔG° were determined using Vant’t Hoff plots. The XRD and FTIR spectral analysis were defined that adsorption was physisorption.

A comparison of anionic and cationic dye removal efficiency of industrial bauxite waste red-mud

Sorption characteristics of the acid-activated bauxite waste red-mud for Nylomine-Blue and Methylene-Blue were investigated to predict its potential removal ability for anionic-di-anthraquinone and cationic-thiazine-dyes, respectively. Surface characteristics of the red-mud were examined using atomic-force-microscopy, diffuse-reflectance-Fourier-transform, and X-ray-diffraction spectroscopy techniques. Kinetic data obtained at four different temperatures fit well to the pseudo-second-order and homogeneous-surface-diffusion models. The experimental Nylomine-Blue sorption capacity (0.020 mmol/g) is higher than that of Methylene-Blue (0.012 mmol/g) at 288 K but they change oppositely with the temperature and attain 0.013 and 0.043 mmol/g at 318 K, respectively. Experimental equilibrium data for Methylene-Blue and Nylomine-Blue are well predicted by the Freundlich, Langmuir, and Dubinin-Radushkevich isotherm equations. The mean-sorption-energies fall into the ion-exchange range for Methylene-Blue but electrostatic-attraction-forces play a more important role in Nylomine-Blue sorption. These mechanisms were correlated to the pH changes in the sorption process and the differences in the diffuse-reflectance-Fourier-transform spectra of dye-loaded sorbents. The atomic-force-microscopy topography and phase images revealed that the hematite and sodalite appear as hills on the red-mud surface but gibbsite and calcite minerals cover the valleys. The Methylene-Blue molecules are sorbed by ion-exchange in the positively-charged-valleys in dilute solutions but Nylomine-Blue is sorbed specifically on overall surface in whole concentration range.

Effectivity of Indonesian Rice Husk as an Adsorbent for Removing Congo Red from Aqueous Solutions

Indonesian rice husk biochar (RH-BC) was prepared by pyrolysis method at 500°C and characterized using X-ray diffraction, Fourier-transform infrared spectroscopy, surface-area-specific analysis by Brunauer-Emmett-Teller, and scanning electron microscopy. The RH-BC were used as adsorbents for enhancing the adsorption of Congo red compared to pristine rice husk (RH) in aqueous solutions. The results of characterization through surface-area-specific analysis showed the surface area of RH-BC (72.25 m2/g) was ten times higher than RH (7.08 m2/g) owing to high-temperature treatment. The results of the adsorption study showed that the RH and RH-BC followed the pseudo-second-order kinetic model and the Freundlich isotherm equation with maximum adsorption capacities of 85.470 mg/g and 72.993 mg/g for the RH-BC and RH, respectively. The thermodynamic parameters of adsorption indicated spontaneous and endothermic processes. The reusability of the adsorbents (RH and RH-BC) showed that they are potentially suitable for extracting Congo red from aqueous solution up to three adsorption-desorption cycles. Their performance sharply decreases after the fourth and fifth cycles.

Preparation of mesoporous batatas biochar via soft-template method for high efficiency removal of tetracycline

In this contribution, we apply a soft-template-assisted hydrothermal route using polyethylene-polypropylene glycol (F127) as soft-template agent and biomass batatas as carbon precursor to synthesis a novel hydrothermal mesoporous biochar (HMC-800) for adsorptive removal of tetracycline (TC) from wastewater. We use the biochar prepared without F127 and direct pyrolytic biochar for comparison. The physicochemical properties of all the studied biochar samples are measured using a suite of characterization techniques. Our results show that the HMC-800 displays the highest specific surface area (286.3 m2/g) and total pore volume (0.249 cm3/g), manifesting the introduction of F127 can result in formation of well-developed pore structures. Regarding adsorption properties, the HMC-800 outperforms other biochar samples for TC removal. Our finding shows that solution with near-neutral pH is favorable for TC removal, and the highest adsorption capacity is observed at initial solution pH value 7. In addition, our findings show that applying the pseudo-second-order kinetic and Freundlich isotherm equation closely models the recorded adsorption behavior. The maximum adsorption capacity is measured to be as much as 238.7 mg/g by Langmuir isotherm model. Pore filling, hydrogen-bonding and n-π interaction are suggested to be the prevailing adsorption mechanisms compared to the other mechanisms. Furthermore, the HMC-800 performs better in regeneration and reuse experiments, making it a promising adsorbent material for TC removal from wastewater.

Fabrication of Manganese-Supported Activated Alumina Adsorbent for Defluoridation of Water: A Kinetics and Thermodynamics Study

Fluoride pollution frequently occurs in many underground drinking water sources due to discrepancies in the geological environment. To address this problem, a manganese-supported activated alumina (MnOOH-supported AA) adsorbent was proposed in the present study. The adsorbent was prepared with an impregnation method, then the morphology and microstructure were systematically characterized. Further, the adsorption kinetics and thermodynamics were systematically explored through static experiments to confirm the adsorption mechanism. The results showed that MnOOH was successfully loaded on the activated alumina (AA), and irregular and convex spinous structures were formed on the surface of particles. Compared with the AA, MnOOH-supported AA exhibited a significantly higher defluoridation rate, which has been doubled. The kinetic behavior of fluoride adsorption on MnOOH-supported AA was governed by the quasi-second-order kinetics model with regression coefficients of 0.9862, 0.9978 and 0.9956, respectively. The adsorption rate was mainly ascribed to the intra-particle diffusion. Additionally, the Freundlich isotherm equation fitted the adsorption thermodynamic process reasonably well compared with the Langmuir adsorption model. Specifically, the correlation coefficients were 0.9614, 0.9383 and 0.9852 at 25 °C, 35 °C and 45 °C, respectively. The adsorption–desorption isotherm plot was similar to the Type V isotherm. The whole fluoride adsorption was a spontaneous endothermic reaction, and controlled by chemical adsorption. These results demonstrated that MnOOH-supported AA as an alternative to the conventional AA showed promising potential for defluoridation in drinking water treatment.

Removal of Cu2+ metal ions from water using Mg-Fe layered double hydroxide and Mg-Fe LDH/5-(3-nitrophenyllazo)-6-aminouracil nanocomposite for enhancing adsorption properties.

Herein, a new adsorbent was prepared by modifying Mg-Fe LDH for the removal of Cu2+ metal ions from wastewater. Mg-Fe LDH with 5-(3-nitrophenyllazo)-6-aminouracil ligand has been successfully prepared using direct co-precipitation methods and was fully characterized using FTIR analysis, X-ray diffraction, BET surface area theory, zeta potential, partial size, TGA/DTA, CHN, EDX, FESEM, and HRTEM. The surface areas of Mg-Fe LDH and Mg-Fe LDH/ligand were 73.9m2/g and 34.7m2/g respectively. Moreover, Cu2+ adsorption on LDH surfaces was intensively examined by adjusting different parameters like time, adsorbent dosage, pH, and Cu2+ metal ion concentration. Several isotherm and kinetic models were investigated to understand the mechanism of adsorption towards Cu2+ metal ions. Adsorption capacity values of LDH and ligand-LDH rounded about 165 and 425mg/g respectively, applying nonlinear fitting of Freundlich and Langmuir isotherm equations showing that the ligand-LDH can be considered a potential material to produce efficient adsorbent for removal of heavy metal from polluted water. The adsorption of Cu2+ metal ions followed a mixed 1,2-order mechanism. The isoelectric point (PZC) of the prepared sample was investigated and discussed. The effect of coexisting cations on the removal efficiency of Cu2+ ions shows a minor decrease in the adsorption efficiency. Recyclability and chemical stability of these adsorbents show that using Mg-Fe LDH/ligand has an efficiency removal for Cu2+ ions higher than Mg-Fe LDH through seven adsorption/desorption cycles. Moreover, the recycling of the Cu2+ ions was tested using cyclic voltammetry technique from a neutral medium, and the Cu2+ ion recovery was 68%.

Chloride ion transport properties in microcracked ultra-high performance concrete in the marine environment

Ultra-high performance concrete (UHPC) has excellent mechanical properties and durability. To determine the allowable tensile deformation range for good durability of these materials in the marine environment, the effects of tensile deformation and subsequent cracking upon the chloride ion permeability properties are investigated herein. The permeability law of chloride ions under tensile deformation is analyzed via marine exposure and indoor immersion testing, and the evolution process of tensile damage and the distribution of steel fibers are characterized by acoustic emission and X-ray computed tomography (X-ray CT) techniques, respectively. The results show that the permeability of chloride ions is larger in the marine environment than in a high chloride-concentration indoor environment. In addition, the permeability of chloride ions is found to increase with the increasing tensile deformation. The relationship between free and bound chloride ions conforms to the Freundlich isothermal equation. Finally, based on Fick's second law, the two-dimensional diffusion process of chloride ions in UHPC is fitted, and the relationship between the tensile deformation and the diffusion coefficient of chloride ions is established.

Optimization delivery of 5-fluorouracil onto different morphologies of ZnO NPs: release and functional effects against colorectal cancer cell lines

The excellent antimicrobial and anticancer efficacy of zinc oxide nanoparticles (ZnO NPs) with strong adsorption capability, low toxicity, low-cost and biocompatibility have spun these nanomaterials into one of the drug delivery systems. Herein, we prepared ZnO NPs with different morphologies and particle size using different methods. ZnO NPs were characterized by using Fourier transform infrared spectroscopy, X-ray diffraction, dynamic light scattering, zeta potential analyzer, scanning electron microscopy and transmission electron microscopy. Spheres with different average diameter ranged from 27 to 94.3 nm, flowers like shape with an average diameter of 250 nm, rod like shape with an average diameter of 92 nm, average length of 337 nm and a semispherical nanosheets with an average diameter of 49 nm were obtained. The nanoparticles were loaded by 5-fluorouracil as anticancer drug model. Adsorption capacity is influenced by the morphology and the size of nanoparticles. Kinetics using pseudo-first-order, pseudo-second-order and intra particle diffusion models was studied. Adsorption isotherms was explored using Langmuir, Freundlich and Temkin isotherm equations. Antibacterial activity of ZnO NPs onto gram-negative and gram-positive bacteria was studied by using disk diffusion agar method. The release of 5-fluorouracil from loaded ZnO NPs was studied at different pH media (2, 7.4) by using UV–visible spectrophotometer. 5-fluorouracil loaded ZnO NPs were examined against colon cancer (HCT) cell line. The spheres and flower-loaded drug showed higher efficacy than pure drug against colon cancer cell line. The results suggest that changing ZnO NPs morphology and particle size will affect antibacterial, anticancer activity, loading capacity of 5-fluorouracil and release profile.

Effects of microplastics on the removal of trace organic compounds during ozonation: Oxidation and adsorption of trace organic compounds and byproducts.

Trace organic compounds (TOrCs) and microplastics (MPs) have been recognized as emerging pollutants that cause severe water pollution related problems due to their non-degradable and bio-accumulative nature. Many studies on oxidation processes such as ozone have been conducted to efficiently remove TOrCs in water treatment. However, there has been a lack of research on the removal efficiency of TOrCs in the oxidation process when they co-exist with MPs and form transformation byproducts (TBPs) during this process. This study evaluates the effects of MPs on TOrC removal during ozonation at various ozone concentrations and based on the mass of MP particles in distilled water. The adsorption of TBPs and TOrCs was also evaluated using the Freundlich and Langmuir isotherm equations. The toxicity of these compounds was evaluated to confirm the risk to aquatic ecosystems. The results show that triclosan (TCS) had the highest absorption capacity amongst the TOrCs and TBPs tested. Polyvinylchloride exhibited the highest adsorption efficiency compared with polyethylene and polyethyleneterephthalate (TCS 0.341mg/g) due to its high adsorption capacity and hydrophobicity. In the toxicity test, 2,4-dichlorophenol and 4-chloroaniline as TBPs had a relatively higher toxicity to Vibrio fischeri (a marine bacterial species) than Daphnia magna (a freshwater plankton species).

Ultrasound-assisted solid phase microextraction-HPLC method based on Fe3O4@SiO2-NH2-molecularly imprinted polymer magnetic nano-sorbent for rapid and efficient extraction of harmaline from Peganum harmala extract

In the present study, a magnetic molecularly imprinted polymer (MMIP) was synthesized for the extraction of harmaline from Peganum harmala by dispersive solid-phase microextraction (DSPME). The MMIP for selective and intelligent extraction of harmaline with excellent functionality and high selectivity was synthesized using the sol-gel method with functionalized superparamagnetic core-shell nanoparticles, ethylene glycol dimethacrylate (EDMA) as a cross-linker, methacrylic acid (MAA) as a functional monomer, and 2,2-azobisisobutyronitrile (AIBN) as a porogen. To study the properties and morphology of the coated polymer, FT-IR spectroscopy, FESEM, TEM images, and VSM were used. The DSPME-HPLC-UV equipment was used to quantify and analyze the data obtained from harmaline extraction. In this research, the efficiency of the synthesized polymer in harmaline extraction was modeled and optimized using the response surface methodology based on central composite design (RSM-CCD). In addition, for modeling the isotherm of harmaline sorption by the MMIP, Langmuir and Freundlich isotherm equations were used. The obtained results showed that the extraction of harmaline with the MMIP was well described with Freundlich isotherm. The results of the validation of the method showed that the measurement of harmaline in the concentration range of 1.0–4000 ng mL−1 followed a linear relationship (R2 = 9986.0). Moreover, the accuracy or repeatability index (% RSD) was determined to be < 10, and the LOQ and LOD values were 0.526 and 0.158 ng mL−1, respectively. The results of this study showed that the DSPME technique by using the synthesized MMIP as an effective sorbent with high efficiency and capacity could be utilized for pre-concentration and extraction of harmaline from real and complex samples.