Best Adsorption Conditions Research Articles

Effective Lead Ions (Pb2+) Mitigation in Battery Industry Wastewater via NaOH-Activated Water Hyacinth (Eichhornia crassipes)

Lead, which is one of the most important heavy metals, is a worldwide toxic pollutant. Adsorption is one of the methods used to study the removal of heavy metal ions from solutions, which encourages us to study the reduction of Pb2+ concentrations in wastewater from the battery factory in this study. The best conditions for adsorption were found using a bioadsorbent called 0.5 M NaOH-activated water hyacinth. This was studied using FTIR to identify the plant. This research conducted adsorption tests on a 20 ppm Pb2+ standard solution, varying the contact times to 20, 30, 40, 50, 60, 70, 140, 210, and 280 minutes. At the contact time of 140 minutes, the Pb2+ concentration reduced to 0.1558 ppm with a 98.0881% adsorption efficiency. Before the bioadsorbent treatment, the FTIR analysis of O-H, C-H, C=C, and C-O functional groups showed that cellulose was present. Activation eliminates the C=C peak and reduces the intensity of the O-H peak. This shows that the lignin and hemicellulose chains are breaking down. When the bioadsorbent binds to Pb2+, the vibrational frequencies of the C-H and C-O groups change, which shows that it works. The results show that the water hyacinth bioadsorbent activated by NaOH is a good alternative material for dealing with Pb2+ waste, which lowers the amount of lead in industrial waste water by a large amount.

Adsorption and desorption strategy for recovering β-carotene from crude palm oil: Kinetics, equilibrium and thermodynamics studies

Palm oil uses are widespread in several industry segments. During refining process, minor compounds such as carotenoids, phytosterols, squalene and tocotrienols are lost. The β-carotene is lost due to the bleaching and the high temperature in the deodorization step. The aim of this work is to recover β-carotene before its degradation in the refining process, using adsorption-desorption strategy. Batch adsorption studies were evaluated for five adsorbents: Diaion HP20, Sepabeads SP70, Sepabeads SP700, Diaion HP2MGL, Amberlite XAD7HP. Modeling of kinetics and equilibrium curves were performed for the Sepabeads SP70, which had the best performance in adsorption. The best conditions for adsorption were at the concentration of 30% (w/w) oil in isopropyl alcohol (IPA) micelle at 30 °C for 180 min. Thermodynamics parameters of adsorption revealed a favorable, spontaneous and exothermic process associated with physical bonding. The studies performed on adsorbent reutilization proved that the regeneration is effective and allows the material reuse at least for 5 cycles without changing the adsorption capacity. Additionally, desorption was evaluated in single and multiple steps and the final enrichment factor was 3.40 ± 0.21. This process allows the palm oil utilization for edible purposes after the adsorption step while recovering β-carotene based on its physicochemical characterization.

Adsorption of remazol golden yellow dye from aqueous solution by acerola core: kinetic and equilibrium studies

This work was conducted to evaluate the efficiency of the acerola (Malpighia emarginata) core as adsorbent (ACB) and as a precursor of adsorbent charcoal (CAB) and activated charcoal (ACP), to remove the textile dye remazol golden yellow (RGY) in solution. The adsorbents characterization was obtained by Fourier-transform infrared spectroscopy, thermogravimetric analysis (TG) and determination of the specific area and the point of zero charge (pHpzc). The best conditions for adsorption for this adsorbent was reached through adsorbent mass studies and kinetic and equilibrium assays. The adsorption capacity q (mg.g-1) was used to analyze the effects. The pHpzc were 4.15 for ACB, 6.00 for CAB and 4.32 for ACP, demonstrating superficial charge favorable to dye adsorption. Considering the kinetic aspects, the pseudo-first order model adjusted more satisfactorily to experimental data. Related to isotherms, Langmuir was more efficient to represent experimental data of dye adsorption. ACB, CAB and ACP are potential adsorbents for dyes in effluents, presenting maximum adsorption capacity, in the study conditions, of 52.35 mg.g-1, 16.40 mg.g-1, and 119.00 mg.g-1, respectively.

Removal of a Textile Azo-Dye (Basic Red 46) in Water by Efficient Adsorption on a Natural Clay

Removal of textile azo-dyes from industrial wastewater is a concerning problem in the modern societies. Adsorption of organic dyes is an alternative for removing these pollutants, but efficient and low-cost adsorbents are required. In this work, a natural (crude) bentonite was used as adsorbent to remove a model cationic (basic) textile dye (basic red 46). Some parameters such as initial dye concentration, time, pH, and temperature were studied in semi-batch experiments to obtain the best conditions for adsorption of basic red 46 (BR-46) with minimal quantity of adsorbent (10 mg in 100 mL of solution). An experimental adsorption capacity (qm) of 594 mg g−1 was determined directly from the adsorption curve for 60 mg L−1, pH=7 and 25 °C. The thermodynamic parameters ΔG°, ΔH° and ΔS° were also estimated. Several adsorption isotherms (Langmuir, Freundlich, and Temkin) and kinetic models (pseudo-first order, pseudo-second order, and intra-particle diffusion) were applied to the experimental data; thus, the best settings were obtained by Langmuir isotherm and pseudo-second order kinetic model. The comparison of results obtained for this natural bentonite with respect to some materials published in the literature reveals the excellent performance of this material for adsorption of BR-46, allowing a fast and higher removal (94% ± 4, at 10 min), under mild conditions (neutral pH, 25 °C and atmospheric pressure).

Use of Aluminosilicate Residue from Insulators of High Voltage Transformers for the Adsorption of Basic Dyes

In this study, an aluminosilicate residue from insulators of high voltage transformers was used for the adsorption of basic dyes. The absorbent was characterized by X-ray fluorescence analysis, X-ray diffraction analysis, scanning electron microscopy, multimolecular adsorption theory (Branauer-Emmet-Teller (BET)) and determination of the point of zero charge (pHPZC). The effect of solution pH and adsorbent mass, the kinetic and thermodynamic behavior at different temperatures and the application of non-linear isotherm models of Langmuir, Freundlich, Temkin and Dubinin-Radushevich were investigated. The pHPZC value for the aluminosilicate was 3.7. The best conditions for adsorption of methylene blue and crystal violet dyes were pH 8.0 and adsorbent mass of 1100 mg in 25 mL. The best fit for the experimental data was obtained applying the pseudo-second-order kinetic model, with an equilibrium time of 480 to 720 min, and the activation energy suggests a physical adsorption mechanism. Isothermal parameters suggest a heterogeneous, favorable and predominantly physical surface adsorption. The thermodynamic studies indicated that the adsorption process is not spontaneous and is exothermic and the Gibbs energy values (ΔGº) suggest physisorption.

Efecto de la dosis de adsorbente y concentración inicial en la remoción de Pb(II) usando cáscara de Opuntia ficus Indica

The effect of the adsorption capacity of Pb (II) on the shell of Opuntia ficus (tuna) was evaluated as a function of the adsorbent dose and initial contaminant concentration, in a batch system. The biomaterial was characterized by a nitrogen adsorption-desorption isotherm applying the BET equation, obtaining a surface area of 2.105 m2/g. FTIR reported the presence of hydroxyl, carbonyl, alcohol and methoxy groups. SEM analysis showed that the surface of the tuna shell has the presence of mesopores and that after adsorption Pb (II) forms micro-complexes and precipitations in the exposed area due to ion exchange with the functional groups. EDS analysis after adsorption confirmed a high content of the metal in the tuna shell. 0.1 g of adsorbent and 90 mg/L were determined as the best conditions for adsorption, reporting a maximum removal capacity of 40.97 mg/g. The pseudo second-order and Elovich models adjusted the experimental data on kinetics; the isotherm was described by the Langmuir equation, determining that the process is controlled by chemisorption and occurs in a monolayer. The results found have potential application in the treatment of wastewater from some industries and mining in South America and the Caribbean Region.

Ultrasonic assisted synthesis of Kaolin/CuFe2O4 nanocomposite for removing cationic dyes from aqueous media

In this study, a new nanocomposite of kaolin/copper iron oxide (CuFe2O4) was synthesized and its characteristics were determined using various analyzes such as FTIR, SEM, XRD, BET, VSM, and EDX/Mapping. According to the results, the specific surface areas of kaolin and kaolin/CuFe2O4 composite were obtained as 10.023 and 174.78 m2/g, respectively, which indicated a significant specific surface area for kaolin/CuFe2O4 nanocomposite. The nanocomposite was then used to remove cationic dyes of methylene blue (MB) and methyl violet (MV) from an aqueous media in a batch system. The results demonstrated that the best conditions for adsorption of MB and MV dyes occurred at pH: 8, with an adsorbent concentration of 1.5 g/L, the initial dye concentration of 10 mg/L, the contact time of 30 min, and a temperature of 25 °C. Under the optimal conditions, the removal efficiency of MB and MV dyes using kaolin/CuFe2O4 nanocomposite were obtained as 98.64 % and 99.25 %, respectively, which show the highest removal ever achieved for MB and MV. Also, the highest sorption capacity of MB and MV dyes using Langmuir model were obtained as 120.48 and 117.65 mg/g, respectively, which show the highest adsorption capacity ever achieved for MB. Moreover, the reusability of the adsorbent was studied and the results showed that that adsorbent could be successfully used in the removal of MB and MV dyes after seven cycles of adsorption/desorption. Furthermore, the thermodynamic study showed that the sorption process was exothermic.

Removal of Azo Dye Calcon Using Polyaniline Films Electrodeposited on SnO2 Substrate

In order to find simple, effective and economical methods for dye adsorption, the present work aims at studying the adsorption efficiency of an azo dye “Calcon’’ by polyaniline (PA) films prepared by the electrochemical method. The characterization of these films by X-ray diffraction (XRD), scanning electron microscopy (SEM) and UV–visible spectrophotometer showing an amorphous fibrillary structure of the PA electrodeposited. To find the best conditions for adsorption of Calcon dye, the effect of pH, hydrogen peroxide, contact time and the initial Calcon concentration were studied. These experiments showcased the possibility of increasing the adsorption capacity from 42% to 54% changing pH from 9 to 3. This value increases to 98.6% by the addition of hydrogen peroxide. On the other hand, the effect of Calcon concentration was studied from 15 to 50 mg/L, the results indicated that the discoloration of Calcon dye decreases with the increase of the dye concentration. However, Kinetics and isotherm studies have shown that the adsorption reaction follows the pseudo-second-order model, the adsorption process follows the Langmuir isotherm model, and the PA electrodeposited has a monolayer adsorption capacity of 606mg/g which is considerably high compared to all polyaniline forms prepared chemically.

Adsorption of Albumin and Creatinine on ZnO Nanoparticles

This study focused on the adsorption of albumin and creatinine on the surface of zinc oxide nanoparticles. Factors affecting adsorption, like contact time, adsorbent dose, concentration, temperature, PH, and shaking rate, were studied. The best conditions for adsorption were found at 298k, pH = (7), the concentration of (2.25, 0.5x10-3)g/dL, (30, 2.5)min, and weight of zinc oxide NPs (30, 10)mg for both albumin and creatinine respectively. We found that adsorption corresponds to Langmuir adsorption isotherms for albumin and Temkin adsorption isotherms for creatinin. Thermodynamic parameters were determined (average of ΔG = -12563.57(J/mol.K), ΔH = 25.740(kJ/mol), average of ΔS = 126.37(J/mol)) for albumin and (average of ΔG = -3348.45(J/mol.K), ΔH = 36.731(kJ/mol), average of ΔS = 132.22(J/mol)) for creatinine, Through the results of )ΔG(, the system is spontaneous because of the negative values. Positive ) ΔH( value clarify that process is endothermic. While ΔS value refers to the system is more random, the results also show that the adsorption type was physical, which means that it is multilayered. The type of bonding force between the molecules is Vander Waals force.

Adsorption of Chromium(VI) onto Freshwater Snail Shell-Derived Biosorbent from Aqueous Solutions: Equilibrium, Kinetics, and Thermodynamics

In this study, freshwater snail shells (FSSs) containing CaCO3 were used as a low-cost biosorbent for removing Cr(VI) from aqueous solutions. The characteristics of FSS and mechanism of Cr(VI) adsorption onto FSS were investigated. The FSS biosorbent was characterized using nitrogen adsorption/desorption isotherm, X-ray diffraction, scanning electron microscopy with energy dispersive spectroscopy, and Fourier transform infrared spectroscopy. The adsorption mechanism was determined by conducting various batch adsorption experiments along with fitting experimental data with various adsorption models. Batch adsorption experiments were conducted as a function of solution pH, contact time, biosorbent dose, and initial Cr(VI) concentration. Results indicated that pH = 2, a contact time of 120 min, and an initial Cr(VI) concentration of 30 mg/L at 20°C were the best conditions for adsorption of Cr(VI) onto FSS. The Cr(VI) adsorption onto FSS decreased with an increase in temperature from 20 to 40°C. The obtained maximum adsorption capacity was 8.85 mg/g for 2 g/L of FSS dose with 30 mg/L of initial Cr(VI) at 20°C. The adsorption equilibrium data fit well with the Sips and Langmuir isotherm models at 20°C with a high R2 of 0.981 and 0.975, respectively. Also, a good correlation between the experimental data and the pseudo-second-order model was achieved, with the highest R2 of 0.995 at 20°C. The adsorption mechanisms were electrostatic interaction and ion exchange. Simultaneously, this mechanism was also controlled by film diffusion. The Cr(VI) adsorption process was irreversible, spontaneous (−∆G°), exothermic (∆H° is negative), and less random (∆S° is negative). In conclusion, freshwater snail shells have the potential as a renewable adsorbent to remove toxic metals from wastewater.

Reuse of dye-colored water post-treated with industrial waste: Its adsorption kinetics and evaluation of method efficiency in cotton fabric dyeing

In this study, the potential for the use of an industrial waste (IW) as an adsorbent for the treatment of aqueous solutions containing C.I. Direct Black 22 was investigated. A kinetic study was performed to investigate the best conditions for adsorption, evaluating the effect of temperature and the adsorbent mass on the thermodynamics of the adsorption processes. Under the best conditions, 95.7% efficiency was achieved within 24h. Pseudo-second-order kinetics models were applied to the experimental data and the correlation coefficients (r2) were higher than 0.98. The treated water was successfully reused in a cotton dyeing process. The best results were obtained with thermally-treated industrial waste, where lower color difference (ΔE) values were observed (0.32–0.70) for dye concentrations of 0.5, 1.0 and 1.5% (w/w). In the case of the raw industrial waste, ΔE values of 0.54 (1.5%, w/w, dye) and 1.36 (2.0%, w/w, dye) were obtained.

Immobilized phospholipase A1-catalyzed acidolysis of phosphatidylcholine from Antarctic krill (Euphausia superba) for docosahexaenoic acid enrichment under supercritical conditions

This paper describes the use of immobilized phospholipase A1 (PLA1) for the production of phosphatidylcholine (PC) rich in docosahexaenoic acid (DHA) using PC from Antarctic krill and fish fatty acids (FA) as the substrates, and supercritical carbon dioxide (SCCO2) as the solvent medium. Detailed studies of immobilization were performed, and PLA1 was immobilized by physical adsorption onto DA-201. The best conditions for adsorption were as follows: protein loading=85mg PLA1/g support at a pH of 5 with 10h of contact. For synthesis of PC with high levels of DHA, the effects of several parameters, including pressure, reaction time, temperature, enzyme loading and substrate molar ratio, were investigated to determine optimal conditions. The optimal substrate molar ratio of the FA to PC was 10. Under 12MPa and 50°C SCCO2, 59.0mol% DHA was incorporated into PC after only 7h at an immobilized enzyme loading rate of 15wt% of the total substrates. The PC yield was 27.5mol% under the optimal conditions.

Removal of dyes by lignocellulose adsorbents originating from biodiesel production

In this study, use was made of tucumã cake, in natura (TCN) and thermally treated (TCT), as potential alternative adsorbents for the adsorption of cationic and anionic dyes. The effects of the parameters: contact time, adsorbent: adsorbate mass ratio, and initial concentration of dye were analyzed. The adsorption isotherms were established from optimized adsorption parameters. The best conditions for adsorption were: equilibrium time of 7h, concentration of 25mgL−1 and ratio of 1:200 for the methylene blue dye; and pH 6.5, concentration of 25mgL−1 and ratio of 1:200 for the congo red dye. The adsorption process was best represented by the Dubinin–Radushkevich and Sips isotherms. The kinetics of adsorption of the dyes were best described by the pseudo-second-order kinetic and Elovich models. TCT showed the best maximum adsorption capacity (Qm) for the methylene blue dye (63.92mgg−1).

Study on adsorption specificity of HB-H-6 resin

Objective The aim of this article was to deeply study the effects of different molecular weight of proteins and different structures of chemical substances on the adsorption specificity of HB-H-6 resin.Methods HB-H-6 resin was adopted to adsorb 5 different molecular weight proteins and different structural chemical substances including proteins,saccharides,human serum albumin (HAS),dextran and lipid,and then underwent static adsorption experiments in vitro.The adsorption rates of different structural chemical substances were analyzed from two experiments and the results were compared.Results The experiment results of HB-H-6 resin adsorption showed that the average adsorption rates of 5 different molecular weight proteins,myoglobin (Myo,16 700),ovalbumin (OVA,44 000),HAS (66 200),β-gal (130 000) and IgG (150 000),were significantly different:(0.00±0.33)％,(8.02± 1.23)％,(43.19±2.31)％,(34.25±1.07)％ and (0.00±0.69)％.In the studies on adsorption of different structural chemical substances,the average adsorption rates of different structural chemical substances proteins,saccharides,lipid were significantly different:the absorption rates of plasma total protein,albumin,globulin,glucose,triglyceride and cholesterol groups were:(11.18±0.72)％,(10.74±0.66)％,(11.74± 1.22)％,(7.17±0.12)％,(1.06± 1.04)％,(3.05± 0.65)％.The absorption rates of HAS and dextran groups were:(43.19±2.31)％ and (5.44±1.46)％.Conclusion In conclusion,the proteins' molecular weight of best adsorption condition is from 66 Ku to 130 Ku.The average adsorption rates of different structural chemical substances proteins,saccharides,lipid are significantly different.The average adsorption rates of proteins are higher than that of saccharides and lipid.It shows that HB-H-6 resin has adsorption specificity on different molecular weight proteins and different structural chemical substances. Key words: HB-H-6 resin; Adsorption; Specificity; Chemical struture

Enrichment of lecithin with n-3 fatty acids by acidolysis using immobilized phospholipase A1

A commercial phospholipase A1 (Lecitase® Ultra) was immobilized by physical adsorption on Duolite® and then used to mediate the incorporation of omega-3 fatty acids into lecithin. Adsorption isotherms showed that 12 h of contact were sufficient to deposit most of the enzyme onto the carrier. A pH of 7 and 50°C were the best conditions for adsorption. Reaction mixtures consisting of lecithin and a saponified fish oil concentrate (78.4 mol % EPA+DPA+DHA) were prepared at molar ratios ranging from 1:2 to 1:10. Typically 2 g of total substrates and 200 mg of enzyme preparation were employed in batch reactor trials. The fastest reaction rates were observed when a substrate mole ratio of 1:8 (lecithin:total fatty acids) was employed. Use of the enzyme preparation dried at pH 8 and reaction temperatures of 50 and 60°C produced the greatest extent of incorporation of the indicated n-3 fatty acids into the phospholipid after 24h of reaction.

Thermoanalytical study of corticosteroid adsorption/desorption on a cellulosic polymer

The aim of this work was to study the adsorption/desorption processes of two corticosteroids (6-methylprodnisolone and sodium hemisuccinate of 6-methylprednisolone) on a cellulosic polymer of ethylcellulose, the commercial latex, Aquacoat®. We measured the time, pH and concentration of the drug necessary to produce the best adsorption and its subsequent release. The data were obtained with spectrophotometry and differential scanning calorimetry. Several overlapping mechanism appeared be involved in the adsorption of the drugs. Identification of these mechanisms helped to determine the best conditions for adsorption, and to predict degradation of the drugs.