Pseudo-second Order Model Research Articles

CTAB Surfactant Promotes Rapid, Efficient, and Simultaneous Removal of Cationic and Anionic Dyes through Adsorption on Glycerol/Citrate Polyester

The discharge of dye waste by industries has caused environmental impacts on water properties, aquatic species, and human life. The production of eco-friendly materials for dye removal from wastewater has gained increasing interest, particularly through adsorption, as it is an efficient method for removing pollutants. However, the selectivity and limited adsorption capacity of materials for simultaneously adsorbing cationic and anionic dyes make it challenging to address the prevailing dye effluent issue. In this work, a poly(glycerol citrate) polyester was prepared without a solvent, using microwave heating, and was combined with cetyltrimethylammonium bromide (CTAB) to modulate the simultaneous adsorption of cationic (Rhodamine B, RB) and anionic dyes (acid blue 113, AB and acid red 27, AR). The formation of the polyester was successfully confirmed by ATR-FTIR and the thermal properties were evaluated by TGA and DCS. In the presence of CTAB 5 mM, the material removes almost 100% of the dyes, reaching the kinetics equilibrium in 30 min following the Pseudo-second order model. Additionally, dye adsorption on the polyester in the presence of CTAB was described by the Freundlich isotherm model, indicating a heterogeneous polyester surface that promotes a multi-layer adsorption driven by electrostatic interaction and hydrogen bonds. The material showed an adsorption capacity of 73.7 ± 3.2, 82.1 ± 4.4, and 21.2 ± 0.6 mg/g for RB, AB, and AR, respectively. Our results provide evidence that the poly(glycerol citrate)/CTAB has a higher potential for application in wastewater treatment to remove both anionic and cationic dyes.

Separation studies of 60Co (II) and 134Cs (I) radionuclides from aqueous solution using starch-grafted citric acid-acrylamide/magnesia hydrogel

Abstract In this study, three starch hydrogels composite prepared using different ratios of starch, citric acid, acrylamide, and MgO nanoparticles (referred to as St1-g-(CA-AM), St2-g-(CA-AM), and St3-g-(CA-AM) MgO). These materials were assessed using FT-IR, SEM, and EDX. The adsorption of 134Cs(I) and 60Co (II) onto these materials studied using radiometric analysis. The investigation focused on how temperature, contact duration, initial metal ion concentration, and pH of the solution affected the sorption efficiency. It is found that a pH value of 7 optimized the adsorption reaction, reaching equilibrium after 40 minutes. The kinetics of the adsorption followed a pseudo-second order model. The Langmuir model adequately explained the sorption mechanism, supported by the analysis of isotherm models. The monolayer adsorption capacities for 60Co (II) and 134Cs (I) were 113.38 and 100.2 mg g−1, respectively. The thermodynamic study indicated that the sorption process is both endothermic and spontaneous.

Адсорбционное извлечение аминов из водных растворов

Aquatic biological resources are an important part of the ecosystems of our planet, since they are involved in economic turnover as a source of food. The composition of water, including waste water from enterprises, has a direct impact on the state of aquatic biological resources. To extract and concentrate metals from solutions, hydrometallurgical processes are used – extraction and sorption. Their implementation is possible with the use of special substances – extractants and in a number of processes – sorption materials (Solvent Impregnated Resins (SIR’s) and Levextrel’s) with a mobile phase of the extractant, combining the properties of sorbents and extractants. Despite the advantages of the latter, such as high kinetic parameters, lack of swelling and high values of mechanical strength, they are characterized by the disadvantages of extraction methods – the entrainment of the extractant into the aqueous phase in dissolved and emulsion forms. Under static conditions, the possibility of purification of aqueous solutions containing primary or tertiary amine by adsorption on carbon materials (activated carbon NWC, carbon NWC-T modified with carbon nanotubes, CS-PTFE modified with polytetrafluoroethylene), as well as on styrene-divinylbenzene nonionic copolymer Porolas-T and a natural shell rock adsorbent was studied. The kinetics of adsorption of аmines Primene-JMT and TOA from aqueous solutions by these adsorbents has been studied by the method of a limited volume of solution. Of the known pseudo-first order, pseudo-second order and Elovich models, the pseudo-second order model describes kinetic data more adequately (R2>0.99). The values of the distribution coefficients and the rate constants of adsorption of Primene-JMT and TOA are determined. A block diagram of adsorption purification of aqueous solutions from amines is proposed, the implementation of which will reduce the toxicity of waste solutions and return some of the expensive extractant to circulation.

The modified pomegranate peel as an economical and highly effective adsorbent for malachite green dye removal from wastewater

This research investigated the ability of acid-modified pomegranate peel to remove malachite green (MG) dye from aqueous solutions. Pomegranate peel, an abundant agricultural byproduct, was modified using hydrochloric acid to enhance its adsorption capacity. The effects of parameters like particle size, pH, initial MG concentration, contact time, temperature and adsorbent dosage on the dye removal efficiency were studied. Under optimized conditions of pH 8, 40 min contact time, 25°C temperature and 0.01 g/ml adsorbent dose with 5 mg/L MG solution, about 96.8 % dye removal was achieved. Kinetic data fitted well to the pseudo-second order model, indicating chemisorption with electrostatic interactions governing the adsorption. Equilibrium data were best described by the Temkin isotherm model, suggesting a heterogeneous binding energy distribution. Thermodynamic calculations revealed the exothermic and spontaneous nature of MG adsorption. FTIR analysis confirmed introduction of functional groups like carboxyl, amine and alkyl groups on the adsorbent surface after acid modification, enabling interactions with dye cations. SEM images displayed increased surface roughness and porosity for the modified biosorbent relative to the raw form. The acid-modified pomegranate peel proved to be an economical, eco-friendly and effective adsorbent for removing the hazardous cationic dye MG from wastewater. The findings support agricultural waste valorization for environmental remediation applications.

Effect of Initial pH for Polluted River Water Treatment Via Pilot Scale Membrane Photocatalytic Reactor (MPR)

Conventional technologies such as physical, chemical, and biological treatment have low efficiency, a tendency towards fouling, and use high energy consumption, respectively.Coagulation-flocculation base treatment, nearly 40-60%, during thelatest technologies as an advanced organic process (AOP) with Fenton-reagents, nearly 80-85% in dissolved organic compound (DOC) reduction, respectively. It proves that emerging technology and new green technology are needed. Therefore, the objective of this study is (i) to treat polluted rivers using pilot-scale MPRs with different initial pH of 5, 7 and 9 and adsorption-desorption time contact for 20, 30 and 40 minutes using 0.05 g/L ZnO-Kaolin loading, 225W light intensity, pressured one bargand 30 minutes’ photocatalytic reaction time. (ii) analysing the physico-chemical quality of the water before and after the treatment as turbidity, ammoniacal nitrogen (𝑁𝑁𝑁𝑁3𝑁𝑁) biochemical oxygen demand (BOD), chemical oxygen demand (COD), dissolved oxygen (DO), and pH levels using the HACH method with 90.89%, 84.93%, 83.19%, 99.38%, 19.47% and 0.63% removal efficiency respectively. (iii) Analyzing the kinetic reaction between the pseudo-first and pseudo-second order models using turbidity data. In conducting the experiment, the sample of polluted river water was taken at Sungai Sembrong, Batu Pahat. From the result obtained, when pH five and time adsorption-desorption time contact for 30 minutes was the optimum condition for degrading and removing the organic matter. Moreover, it obeys the pseudo-second-order model, which relates to the chemisorption processbetween the ZnO-Kaolin and organic compounds. Overall, MPRs are claimed as a promising technology that is environment-friendly for wastewater treatment applications.

Fast and effective hydroquinone adsorption by poly (2-dimethylaminoethyl methacrylate)/zinc oxide nanocomposite hydrogel in textile wastewater treatment

ABSTRACT Hydroquinone, a widely used phenolic compound, poses significant health and environmental risk and must be removed from wastewater. In this study, a novel adsorbent was developed for the removal of hydroquinone from aqueous solutions through the in-situ polymerisation of 2-(dimethylamino)ethyl methacrylate (DMAEMA) in the presence of zinc oxide nanoparticles (ZnO NPs). The kinetics of equilibrium swelling in deionised water (DI) and the effect of pH on the swelling behaviour were investigated. The structure of the nanocomposite hydrogel was analysed using FTIR, XRD, FESEM, EDX, TEM, and BET analysis. Various factors affecting the adsorption process, such as solution pH (2–12), initial concentration (25–200 mg/L), adsorbent dosage (4.0–80 mg/100 mL), NaCl concentration (0.1–1.0 mol/L), and temperature, were also investigated. The adsorption capacity of hydroquinone and the removal efficiency of PDMAEMA@ZnO reached 455 mg/g and 91%, respectively, at pH 11 within 15 minutes. Furthermore, PDMAEMA@ZnO showed a high removal efficiency of 99.47% in tests with real wastewater. Reusability studies showed that the adsorbent retained its ability to remove hydroquinone after four regeneration cycles. The adsorption data were well described by the pseudo-second order and Langmuir models. The thermodynamic parameters indicated that the adsorption process is spontaneous and endothermic. Therefore, the adsorbent, has considerable industrial potential as it quickly and efficiently adsorbs phenolic impurities such as hydroquinone from real textile wastewater.

Novel dialkylphosphinic acid modified Merrifield resins: Synthesis, characterization, and their adsorption and separation behaviors for zirconium and hafnium

Deep separation of Zr and Hf has always been a great challenging due to their very similar physicochemical properties. In this study, we established a method to synthesize two novel extraction chromatographic resins which graft dialkylphosphinic acid groups through amide group. The dialkylphosphinic acid modified resins were characterized by FT-IR, EA, SEM-EDS, XPS, and BET. Their adsorption and separation behaviors for Zr and Hf were investigated, and the adsorption mechanism was studied. The Zr and Hf adsorption onto Mer-CON-POOH-272 and Mer-CON-POOH-HYY2 both fit pseudo-second order model and Langmuir isotherm model. Mer-CON-POOH-HYY2 has stronger affinity to Zr and Hf than Mer-CON-POOH-272. Mer-CON-POOH-272 has a theoretical maximum loading capacity of 5.663 mg·g−1 Zr and 11.111 mg·g−1 Hf, while Mer-CON-POOH-HYY2 has a higher theoretical maximum loading capacity of 8.376 mg·g−1 Zr and 13.157 mg·g−1 Hf. Dialkylphosphinic acids are the functional groups of Mer-CON-POOH-272 and Mer-CON-POOH-HYY2 that interact with Zr and Hf during adsorption. They adsorb Zr and Hf through cation exchange mechanism, which can be expressed as M(SO4)32– + 2HL ⇌ M(SO4)L2 +.2H+ + 2SO42-. With increasing H2SO4 concentration, the Zr and Hf extraction percentages and their separation efficiency reduce. The DFT calculation reveals that the adsorption process is accompanied by charge transfer. Adsorption occurs mainly at P = O and P-O positions. The affinity of the two resins for Hf is higher than that of Zr, which is the reason why the resin preferentially adsorbs Hf.

Efficient removal of Sb(III) from wastewater using selenium nanoparticles synthesized by Psidium guajava plant extract.

Antimony (Sb) pollution in aquatic ecosystems has emerged as a critical environmental issue on a global scale, emphasizing the urgent need for cost-effective and user-friendly technologies to remove Sb compounds from water sources. In this study, a novel adsorbent, selenium nanoparticles (SeNPs), was synthesized using the aqueous extract of Psidium guajava L. leaves (AEP) for the purpose of eliminating Sb(III) from aqueous solutions. The biosynthesized SeNPs was characterized using scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray fluorescence spectrometer (XRF), Fourier Transform-Infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), Raman spectroscopy and X-ray photoelectron spectroscopy (XPS) analysis techniques. Additionally, the removal efficiency of the SeNPs for Sb(III) was systematic investigated under the effects of SeNPs dose, temperature, pH and re-usability. The results of this study showed that the adsorption data fitted well into pseudo-second order model, while the Sips modeling demonstrated a high adsorption capacity (62.7mg/g) of SeNPs for Sb(III) ions at 303.15K from aqueous solution. The exothermic enthalpy change of - 22.59kJ/mol and negative Gibbs free energy change assured the viability of the adsorption process under the considered temperature conditions. Surface functional groups on SeNPs like carboxyl, amide, hydroxyl, carbonyl, and methylene significantly facilitate the adsorption processes. Furthermore, the removal efficiencies of Sb in the two actual Sb mine wastewater samples were remarkably high, achieving nearly to 100% with 1.5g/L SeNPs within 48h. This outcome underscores the potential of SeNPs as a highly promising solution for efficiently remediating Sb from aquatic environments, owing to their cost-effectiveness, ease of regeneration, and rapid uptake capabilities.

Fabrication of pesticide/LDH-LAP composite assisted by zwitterionic surfactant

Using zinc-aluminum layered double hydroxides-laponite (LDH-LAP) complex as matrix, with the assistance of zwitterionic surfactants of hexadecyl dimethyl sulfobetaine (SB) and dodecyl dimethyl carboxyl betaine (DCB), the pesticides beta-cypermethrin (BCT) and imidacloprid (IMP) were inserted into the LDH-LAP to obtain BCT/SB-LDH-LAP, BCT/DCB-LDH-LAP, BCT/SB-DCB-LDH-LAP and IMP/DCB-LDH-LAP composites, respectively. Powder X-ray diffraction (XRD), fourier transform infrared spectroscopy (FT-IR), thermogravimetric/differential thermal analysis (TGA/DTA) and scanning electron microscope (SEM) were used to characterize the structural properties of composites. BCT/SB-LDH-LAP, BCT/DCB-LDH-LAP, BCT/SB-DCB-LDH-LAP and IMP/DCB-LDH-LAP had larger interlayer distances of 4.29, 4.33, 4.33 and 4.61 nm, which were bigger than those of SB-LDH-LAP (3.87 nm), DCB-LDH-LAP (3.83 nm) and LDH-LAP (1.65 nm). The FT-IR and TGA/DTA results further confirmed the existence of SB, DCB, BCT and IMP into LDH-LAP. The pesticide releases were investigated and analyzed in pH 5.0 and 6.8 buffer solutions. The release behaviors can be fitted by pseudo second-order and parabolic diffusion models. The composites based on LDH-LAP could be suggested to potential application for controlled-release of the pesticide.

Synthesis of hydroxyapatite/activated carbon composite with bioactivity property and copper ion removal efficiency

Hydroxyapatite/activated carbon composite (HAP/AC) was synthesized via a one-pot method for an adsorption removal of copper ions (Cu2+) in water. The surface area, average pore size and pore volume of HAP/AC were found to be 296.41 m2 g−1, 3.5929 nm and 0.1509 cm3 g−1, respectively. The HAP/AC showed the Cu2+ removal efficiency of 99.68 % with the adsorption capacity of 299.05 mg g−1 at the initial concentration of 300 mg L−1, 50 °C and pH 5. The adsorption capacity of HAC/AC was higher than that of HAP and bare AC. The interaction between Cu2+ and HAP/AC adsorbent was suggested to be complexation, cation exchange, and electrostatic interaction. The adsorption followed the Freundlich isotherm model, indicating a non-uniform distribution of adsorption sites that led to multilayer adsorption with various binding energies. The adsorption kinetics fit well with the Pseudo-second order model with the amount of Cu2+ ions adsorbed at an equilibrium of 357.14 mgg−1. Thermodynamic studies indicated that the adsorption was spontaneous and endothermic with an increase in the randomness at the solid-liquid interface. In addition, the bioactivity test of HAC/AC showed that the growth of the newly-formed apatite increased with soaking time, demonstrating its potential in orthopedic implantology.

Performance evaluation of sugarcane bagasse biochar based fixed bed column for removal of triclosan from aqueous solution in presence of humic acid: Mechanism, kinetics and safety

Triclosan (TCS), an emerging pollutant emerges as a notable contributor to adverse impacts on aquatic organisms owing to its widespread use during COVID19. The current study aims to investigate the efficiency of sugarcane bagasse biochar (SBB) for removal of triclosan (TCS), an emerging pollutant in aquatic ecosystems in presence of humic acid from aqueous solution through batch and column studies. In batch study, SBB prepared at pyrolysis temperature of 400 °C showed highest adsorption of TCS. Langmuir isotherm model showed highest adsorption of 68.49 mg g−1 at pH 7.0. A 90 % reduction in TCS was accomplished with 0.625 g L−1 of SBB-400 °C. Adsorption kinetic modelling was well fitted to pseudo-second order model signifying that rate of adsorption on SBB-400 °C mainly depends on chemisorption. TCS removal was not significantly inhibited in presence of 5, 10 and 25 mg L−1humic acid concentrations. Column experiments of continuous flow biochar-bed column with the aqueous solution spiked with TCS (100 mg L−1) at a flow rate of 50 mL min−1 showed 99 % removal efficiency. Thomas model and Yoon-Nelson model signified the breakthrough behaviour of TCS adsorption on the column and the experimental data were in good agreement with the expected values. Bioassay studies on Chlorella vulgaris exhibited that percentage inhibition (8 %) in algal cell counts was significantly less in the SBB treated TCS water when compared with control (untreated water containing TCS). The designed column is highly efficient, effective and eco-friendly approach for TCS removal.

Carbon nitride reinforced chitosan/sodium alginate hydrogel as high-performance adsorbents for free hemoglobin removal in vitro and in vivo

Removing free hemoglobin generated during extracorporeal circulation remains a challenge. Currently, there is no adsorbent with specificity and good biosafety for removing hemoglobin. In this study, a new chitosan/sodium alginate/carbon nitride (CS/SA/C3N4) hydrogel adsorbent was prepared by blending SA with C3N4 to drop into CS/CaCl2 solution. The physicochemical properties of CS/SA/C3N4 hydrogel were evaluated using some techniques, including scanning electron microscope, Zeta potential measurement, and thermogravimetric analysis. Hemoglobin adsorption in vitro, stability, hemocompatibility, cell compatibility, inflammatory reaction and blood extracorporeal circulation in vivo were also evaluated. The findings revealed that the CS/SA/C3N4-0.4 % hydrogel exhibited an impressive adsorption capacity of 142.35 mg/g for hemoglobin. The kinetic data of hemoglobin adsorption were well-described by pseudo second-order model, while the isothermal model data conformed to the Langmuir model. The hardness and modulus of CS/SA/C3N4-0.4 % was 11.7 KPa and 94.66 KPa respectively, which indicated robust resistance to breakage. CS/SA/C3N4 demonstrated excellent hemocompatibility, biocompatibility and anti-inflammatory properties. In addition, the results of in vivo rabbit extracorporeal blood circulation experiment demonstrated that CS/SA/C3N4 could adsorb free hemoglobin from blood while maintaining high biosafety standard. Consequently, CS/SA/C3N4 hydrogel emerges as a promising candidate for use as a hemoglobin adsorbent in extracorporeal blood circulation system.

Modifications and applications of aerogel prepared with waste palm leaf cellulose in adsorptions for oily contaminations

Abstract Aerogels are essential and effective materials for oily pollution adsorption and recovery. This work described a hydrophobic modified cellulose aerogel using waste palm leaf and its oil adsorption mechanism. By chemical vapor deposition, Methyltrimethoxysilane (MTMS) was employed as a hydrophobic modifier for aerogel of waste palm leaf cellulose at 80 °C for 5 h, and the modified aerogel demonstrated exceptional and stable hydrophobicity with a water contact angle of 132.4° that can still be maintained above 120° after two months of air exposure. After 10 adsorption and extrusion cycles, kerosene adsorption capacity can still reach over 18 times its weight with good regeneration and reuse performance. The kinetic analysis found that the pseudo-second order model was more appropriate for the aerogel’s oil absorption process, including mainly physical adsorption at the beginning and the following chemical adsorption. Owing to its low cost, hydrophobicity, high absorption capacity, and favorable reusability, this aerogel is expected to be used in oils, organic solvent spill cleanup, and oil/water separation fields.

Onion Peel: A Promising, Economical, and Eco-Friendly Alternative for the Removal of Divalent Cobalt from Aqueous Solutions

There is a growing need for an economical and efficient method capable of removing heavy metals from residual water. The current contribution aimed to evaluate the capacity of onion peel, an abundant agroindustrial waste product, to remove divalent cobalt (Co2+) from aqueous solutions. Onion peel was submitted to proximal chemical analysis, and various operational factors involved in biosorption were tested. The most suitable temperature (30 °C), pH (7.0), and biosorbent particle size (300–800 µm) were found. With an initial Co2+ concentration of 380 mg L−1, the maximum capacity of Co2+ removal was 59.88 mg g−1 in 120 min. The pseudo-second order and Langmuir models provided the best fit to the experimental kinetics and equilibrium of Co2+ biosorption, respectively. The thermodynamic study evidenced an exothermic, non-spontaneous, and favorable reaction (ΔH0 = −5.78 kJ mol−1; ΔS0 = −21.13 J mol−1 K−1), suggesting the formation of stable bonds in the biosorbent-Co2+ complex. The carbonyl and hydroxyl groups apparently play a fundamental role in Co2+ removal, and electrostatic attraction, ion exchange, and chemisorption are the principal mechanisms. Thus, the biosorption of Co2+ by onion peel has potential as an economical, eco-friendly, efficient, and sustainable treatment for wastewater.

Adsorption of cationic dyes and antibiotics from aqueous solution by dopamine-modified peanut husk

ABSTRACT Dopamine modified peanut husks (PH/DA), a novel adsorbent, were investigated to enhance the adsorption capacity of dyes (neutral red, NR and crystal violet, CV) and fluoroquinolone antibiotics (ofloxacin, OFLX and enoxacin, ENO). Scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared (FT-IR), thermo-gravimetric analysis and differential scanning calorimetry (TG-DSC) and Brunauer-Emmett-Teller (BET) method were used to characterize PH and PH/DA. The findings demonstrated that the physical and chemical properties of the peanut husks were changed after dopamine-modification. As for adsorption kinetics, NR adsorption properties were satisfactorily explained by the Elovich model, whereas CV adsorption processes suited to the pseudo-second order model. Both OFLX and ENO followed the pseudo-first order model. Isotherm data showed that CV and ENO conform to the Temkin model while NR and OFLX fitted better to the Langmuir model. The q max of NR, CV, OFLX and ENO by PH/DA were 52.37, 45.92, 46.57 and 58.40 mg/g at 290 K, respectively, according to Langmuir model. The adsorbent maintained an adsorption efficiency of above 70% even after three adsorption-desorption cycles. These findings proved that PH/DA’s successful development offers important insights into the production of sorbents for water treatment based on biomass.

Design and characterization of phosphonic acid-functionalized grafted sepiolite nanohybrids and their adsorption studies for removal of copper ions from aqueous solution.

In this study, we synthesized novel, economically efficient phosphonic acid-functionalized grafted sepiolite nanohybrids for selective elimination of copper ions from water. These nanohybrids were prepared by graft polymerization of glycidyl methacrylate onto sepiolite. We utilized free radical graft polymerization to graft glycidyl methacrylate (GMA) onto silanized sepiolite. The nanohybrids obtained exhibited a grafting percentage of 479% at 0.3 g of KPS initiator, 15% GMA monomer, and after 4 h of reaction. In pursuit of selectively removing metal ions from water, the nanohybrid with the highest grafting (PGE3) was chemically treated with phosphoric acid to introduce phosphonic acid groups on it. FTIR, XRD, SEM, CHO analysis, BET, and TGA analysis were utilized to characterize the developed nanohybrids. Batch adsorption studies were carried out using AAS process, examining the impact of pH, adsorbent weight, contact time, adsorbate concentration, and temperature on the adsorption process. Due to the selectivity of phosphonic acid groups towards copper ions, phosphonic acid-functionalized grafted sepiolite nanohybrid (PGE3-P) was used for copper ions removal from its aqueous solution. The maximum adsorption capacity of PGE3-P adsorbents was 134.5 mg/g for copper ions. The data from kinetic studies suggests that the adsorption process of copper ions followed a pseudosecond-order model. Furthermore, Langmuir isotherm proved to be a more fitting model in equilibrium isothermal investigations. The thermodynamic analysis of the data indicates that the adsorption of copper ions by PGE3-P is an endothermic and spontaneous process. The development of this phosphonic acid-functionalized grafted sepiolite nanohybrid adsorbent is a new contribution into the field of adsorption. The developed material can be utilized as selective adsorbent for elimination of other heavy metals from water.

Vitamin C-reduced graphene oxide/Fe3O4 composite for simultaneous removal of aflatoxin B1 and benzo(a)pyrene in vegetable oils

Vegetable oils are essential constituent of the daily dietary intake. Nevertheless, they often contain aflatoxin B1 (AFB1) and benzo(a)pyrene (BAP). Physical adsorption is the most commonly used detoxification method in the vegetable oils industry. Regrettably, the previously reported adsorbents have exhibited limited efficacy, rendering them inadequate for meeting the requirements of large-scale production of edible oils. In this work, a superparamagnetic Fe3O4/reduced graphene oxide (rGO) composite was synthesized by a one-step hydrothermal method using vitamin C (VC), and systematically characterized. The Vitamin C-reduced graphene oxide/Fe3O4 composite (VC-rGO/Fe3O4) could serve as an efficient adsorbent in edible vegetable oils for the simultaneous removal of AFB1 and BAP. The results of the batch adsorption studies indicated that the pseudo-second order model and Sips model, respectively, were the best fit kinetic model and adsorption isotherm model. The adsorption of AFB1 and BAP on VC-rGO/Fe3O4 was spontaneous, which included both physical and chemical adsorption processes. The removal efficiencies of VC-rGO/Fe3O4 in 13 vegetable oils were evaluated, revealing a wide range of practical applications. Moreover, the quality and safety of detoxified vegetable oils is acceptable. Therefore, VC-rGO/Fe3O4 have been tested as promising candidates for the simultaneous removal of AFB1 and BAP in edible vegetable oils.

Adsorption of terbutaline β-agonists from wastewater by mechano-synthesized iron oxide nanoparticles modified copper (II) isonicotinate metal-organic framework

Frequent detection of terbutaline in wastewater highlights its potential risks to human health associated in the environment. Exposure to terbutaline through contaminated water sources or food chain have adverse effects to human health. This work emphasized on the removal of terbutaline from wastewater using adsorption technology. Mechanochemically synthesized [Cu(INA)2] metal-organic frameworks (MOFs) and its magnetic composite ([Cu(INA)2]-MOF@Fe3O4) are designed with higher specific surface areas and tailored features to accommodate the molecular size and structure of terbutaline. Thus, batch experiment has been conducted using the [Cu(INA)2]-MOF and [Cu(INA)2]-MOF@Fe3O4 for the terbutaline adsorption. The adsorption efficiency achieved by the MOFs was 91.8% and 99.3% for the Cu(INA)2]-MOF and [Cu(INA)2]-MOF@Fe3O4 respectively. The optimum for the adsorption study included terbutaline concentration of 40 mg/L, adsorbent dose of 5 mg/L, pH of 11, temperature of 25 °C and equilibrium time of 40 min. The kinetics and isotherms have been described by pseudo-second order and Langmuir models, while the thermodynamics revealed the exothermic and spontaneous nature of the process. The promising performance of the MOFs is manifested on the ease of regeneration and reusability, achieving adsorption efficiency of 85.0% and 94.7% by the Cu(INA)2]-MOF and [Cu(INA)2]-MOF@Fe3O4, respectively at five consecutive cycles. The higher performance of the MOFs demonstrates their excellent potentialities for the terbutaline adsorption from the aqueous solution.

Modification of PVA Nanofiber by Simple Hot Water Treatment and Application on the Removal of Malachite Green Dye From Aqueous Solutions.

In this study, the crosslinking of PVA nanofiber was increased using solvent vapor treatment. Then, Fe3O4 nanoparticles were synthesized by a simple hot water technique and composited with the nanofiber. The study focuses on applying the modified PVA nanofibers to remove malachite green (MG) from water using different pH, contact times, and dye initial concentrations. The surface morphology of the nanofiber was determined using SEM, FTIR, and XRD techniques. SEM showed that the crosslinking was increased, and Fe3O4 nanoparticles appeared as agglomerates on the surface of the nanofiber. The removal percentages at optimal pH and contact time were 99.76%, and 99.5%, respectively. Thereafter, kinetics was studied by the linear pseudo-first order, pseudo-second order, Elovich equation, and Intraparticle diffusion models. Results demonstrated that the adsorption kinetics follow the pseudo-second order. Moreover, the adsorption isotherm was discussed using Langmuir and Freundlich equations. The Langmuir equation best described the adsorption with R2 value of 0.9771, and the maximum removal was 128.205 mg/g. As a result, the MG dye molecules covered the PVA nanofiber/Fe3O4 nanoparticles in a monolayer and homogenous coverage. The results of this study are significant for industries' wastewater treatment as they provide a potential solution for the removal of MG dye from textile, paper, cosmetics, food, and aquaculture industries' wastewater.

Mandarin biochar-CO-TETA was utilized for Acid Red 73 dye adsorption from water, and its isotherm and kinetic studies were investigated

Environmental pollution is a major issue today due to the release of dyestuff waste into the environment through industrial wastewater. There is a need for affordable and effective adsorbents to remove harmful dyes from industrial waste. In this study, Mandarin biochar-CO-TETA (MBCOT) adsorbent was prepared and used to remove Acid Red 73 (AR73) dye from aqueous solutions. The efficiency of dye removal was influenced by various factors such as solution pH, contact time, initial AR73 dye concentration, and MBCOT dosage. All experiments were conducted at 25 ± 2 °C, and the optimal pH was determined to be 1.5. The optimal conditions for dye removal were found to be an AR73 dye concentration of 100 mg/L, an MBCOT dosage of 1.5 g/L, and a contact time of 150 min, resulting in a 98.08% removal rate. Various models such as pseudo-first-order (PFO), pseudo-second-order (PSO), film diffusion (FD), and intraparticle diffusion (IPD) were used to determine the adsorption kinetics of AR73 dye onto MBCOT. The results showed that the PSO model best explains the AR73 dye adsorption. Furthermore, Langmuir and Freundlich's isotherm models were studied to explain the adsorption mechanism using experimental data. The adsorption capacities at equilibrium (qe) in eliminating AR73 dye varied from 92.05 to 32.15, 128.9 to 65.39, 129.25 to 91.69, 123.73 to 111.77, and 130.54 to 125.01 mg/g. The maximum adsorption capacity (Qm) was found to be 140.85 mg/g. In conclusion, this study demonstrates that biochar produced from mandarin peels has the potential to be an effective and promising adsorbent for removing AR73 dye from water.