Adsorption Kinetic Studies Research Articles

Utilization of palm leaves powder for removal of Rhodamine-B from an aqueous solution

In this research, adsorption of Rhodamine-B (RhB) from an aqueous solution onto palm leaves powder at room temperature was reported. The adsorption capacity of palm leaves powder was increased with initial concentration of RhB, and contact time while declined with temperature, pH, and mass of palm leaves powder. Results of adsorption kinetics study represented that RhB adsorption fitted to pseudo-second-order model because the value of correlation coefficient (R2 = 0.995) was close to unity. Adsorption isotherm illustrations indicated that RhB adsorption obeyed Langmuir isotherm model with correlation coefficient (R2 = 0.999) close to unity. Results of thermodynamics investigation indicated that RhB adsorption onto palm leaves powder was an exothermic process because the value of change in enthalpy (ΔH°= −16.95 KJ/mol) was negative. Moreover, the positive value of Gibb’s free energy represented that RhB adsorption onto palm leaves powder was a non-spontaneous process. In addition, the regeneration of palm leaves powder was also conducted.

Biosorption of Triphenylmethane (TPM) Dyes by Microbial Biomass: A Review

Many organic and inorganic contaminants are present in wastewater, and releasing them into receiving waterways causes major environmental problems. The wastewater produced by numerous industries contains a significant amount of dyes; this continues to be one of the most serious ecological issues confronting public health. Unfortunately, conventional wastewater remediation methods are incapable of completely removing dyes. Biosorption is the process by which living material removes chemicals from a solution. Organic, inorganic, gaseous, liquid, or insoluble substances are examples of such substances. Absorption, adsorption, ion exchange, surface complexation, and precipitation are all mechanisms involved in this physicochemical process. It is a characteristic shared by both live and dead biomass. Triphenyl methane dyes are a significant category of commercial dyes known for their remarkable color intensity, bright red, green, and blue colors, and low lightfastness on many substrates. In contrast to live biomass, using dead biomass in biosorption is more ideal since the hazardous nature of pollutants does not affect the sorption process. There is also no need to provide nutrients or maintain a growing environment. In addition to these variables, researchers discovered that dead biomass is more efficient than active biomass at absorbing organic contaminants. This review highlighted the toxicity of dyes, principles, and theory of the adsorption process, isotherm and kinetic studies of some microbial biosorbents, and thermodynamic studies of triphenyl methane dyes adsorption.

Comparative removal of pharmaceuticals in aqueous phase by agricultural waste-based biochars.

The intensification of pharmaceutical use globally has led to an increase in the number of water bodies contaminated by drugs, and an effective strategy must be developed to address this issue. In this work, several biochars produced from Miscanthus straw pellets (MSP550, MSP700) and wheat straw pellets (WSP550, WSP700) at 550 and 700°C, respectively, were selected as adsorbents for removing various pharmaceuticals, such as pemetrexed (PEME), sulfaclozine (SCL), and terbutaline (TBL), from the aqueous phase. The biochar characterizations (physicochemical properties, textural properties, morphological structures, and zeta potentials) and adsorptive conditions (contact times, temperatures, and pH effect) were investigated. The infrared and Raman spectra of biochars before and after pharmaceutical adsorption, as well as quantum chemical computations, were carried out to explore the adsorption mechanisms. The results showed that the general adsorption abilities of biochars for pharmaceuticals were in the order of WSP700 > MSP700 > MSP550 > WSP550. Both the higher drug concentration and higher temperature improved biochar adsorption. By decreasing the pH, the adsorption amounts increased for PEME and SCL. However, TBL exhibited the best adsorption at pH7, whereas a weakening of affinity occurred at lower or higher pH values. Electrostatic interactions and hydrogen bonding were the main adsorptive mechanisms between all biochars and pharmaceuticals. π-π interactions played a role in the adsorption process of low-temperature-prepared biochars (MSP550 and WSP550). This work can provide new insights into the control of pharmaceuticals from water with low-cost adsorbents. PRACTITIONER POINTS: Use of biochars for pharmaceuticals removal from aqueous phase. Characterization of biochars : physical and chemical properties, textural and surface properties. Simulation calculation for characterization of pharmaceuticals. Kinetic studies of pharmaceuticals adsorption on biochars. DRIFTS and Raman analysis for the understanding of adsorption process.

Natural clays as adsorbents for the efficient removal of antibiotic ciprofloxacin from wastewaters: Experimental and theoretical studies using DFT method

Natural clays were used as adsorbent to remove ciprofloxacin from aqueous solutions by adsorption. The textural, structural, and morphological properties were examined, finding low-moderate specific surface area values (9.9–50.1 m2g−1) and a structure coincident with the smectite phase. Adsorption kinetic studies revealed that clay 3 and 4 reached a CIP removal around 70–80 % in 7–8 h. Elovich and pseudo-second-order models were the most suitable to describe the kinetics. The highest equilibrium adsorption capacities (qe = 150.2–193.7 mg g−1) were obtained for clay 1, 3, and 4; the lowest (qe = 30.6 mg g−1) was found for clay 2, which showed the highest-ordered structure. The Freundlich adsorption model led to the best-fitting results. From pH studies, working at solution pH = 4.0 led to the best adsorption results. The estimated thermodynamic parameters suggested that the adsorption process can be considered of physical nature. It was found that the high concentration of CO32– salts in the hospital wastewater effluent enhanced the CIP adsorption capacity, showing a CIP removal of about 95 % for the clay 3. Therefore, the adsorbent with the greatest compromise situation among all the variables was clay 3, presenting the maximum CIP removal after 7 h at pH 4.0, 50 °C and real matrices. The reusability of natural clays can be successfully regenerated by NaOH treatment using the adsorption/desorption process, an indication of its excellent reusability and stability during the regeneration. Finally, DFT molecular studies were performed to clarify the particularities of the adsorption of CIP onto clays.

Utilization of Deoxycholic Acid Terminated L-cysteine Modified Mesoporous Silica Nanoparticles as a Nanoadsorbent for Removing Rhodamine B from Contaminated Water: Adsorption Equilibrium and Kinetic Studies

Utilization of Deoxycholic Acid Terminated L-cysteine Modified Mesoporous Silica Nanoparticles as a Nanoadsorbent for Removing Rhodamine B from Contaminated Water: Adsorption Equilibrium and Kinetic Studies

Adsorption and Kinetic study of priority organic pollutant phenol from aqueous waste using Activated carbon

Many organic compounds present in industrial and domestic wastewater are carcinogenic in nature. Removal of these organic compounds from waste waters has become a great challenge to waste water treatment technologies as many of them are non-biodegradable in nature. Adsorption on activated carbon has emerged as an efficient and economically viable technology for the removal of a broad spectrum of toxic organic compounds from domestic and industrial waste water. The adsorption of hazardous organic compounds on activated carbon has been the subject of research for the past three decades. In the present study, kinetic study for adsorption of some priority organic pollutants like phenol on activated carbon, was studied at laboratory scale. Series of experiments were carried out to determine kinetics for adsorbate, when present in aqueous solution as a single component. The commercially available bituminous coal based activated carbon Filtrasorb-400 was used as an adsorbent. A simplified interpretation of the kinetic data based on Langmuir theory has been used. The kinetics performed gives the adsorption equilibrium time. The adsorption and desorption rate constants were evaluated from the graph.

Taguchi method for optimizing the cation exchange resin catalyzed esterification of oleic acid with ethanol and adsorption kinetics study

In this study, solid acid catalysts (cation exchange resins) were used to catalyze the esterification reaction of acidified oil and ethanol for the preparation of biodiesel. The catalyst was characterized by SEM, BET, XRD, and FTIR. The esterification reaction was studied under various conditions using one-way analysis. Process optimization was performed by the Taguchi method, revealing that the optimal conditions for maximum oleic acid conversion (91.63%) were a catalyst dosage of 20 wt%, ethanol/oleic acid molar ratio of 9:1, reaction time of 5 h, and reaction temperature of 80 ℃. In addition, the adsorption behavior of cation exchange resin (S-CER) on oleic acid and ethanol during the esterification process was investigated. The Freundlich and Langmuir adsorption kinetic models of the resin were also established. This study focused on the dynamic equilibrium of oleic acid and ethanol adsorption on the S-CER catalyst surface. The adsorption process was found to align better with the Freundlich isotherm equation. According to this equation, oleic acid's maximum adsorption capacity was found to be 371.24 mg/g. Lastly, a pseudo-primary kinetic equation for the esterification reaction was formulated, and the calculated activation energy for the reaction was 35.59 kJ/mol.

Isotherm Study, Adsorption Kinetics and Thermodynamics of Lead Using Combination Adsorbent of Chitosan and Coffee Ground Activated Carbon

The presence of lead metal in water naturally due to its mobility can cause the nature of water to become toxic and endanger the environmental ecosystem because it bioaccumulates in the food chain. The purpose of this study was to study the maximum adsorption capacity through an isotherm model, to determine the rate of adsorption kinetics in the use of chitosan and coffee grounds adsorbents in reducing lead concentrations in industrial wastewater and to study its thermodynamic magnitude. The research method was carried out using experiments in the laboratory followed by quantitative data analysis to determine the isotherm model and adsorption kinetics. The results showed that the adsorption isotherm follows the Langmuir isotherm model with a correlation coefficient of 0.9970 with a maximum adsorption capacity of 1.0511 mg.g-1 which indicates that chemical adsorption occurs in the mono layer with a homogeneous distribution of adsorption sites with adsorption energy. constant and negligible interactions between lead metal molecules (adsorbate). Study of lead adsorption kinetics using chitosan-activated carbon coffee grounds following the Weber-Morris/intra-particle diffusion model with a correlation coefficient of 0.9920 with a diffusion rate of 76.512 g.mg-1.hour-1 indicating that intra-particle diffusion is the rate step limiting in the overall biosorption process. Negative ΔGo values ​​indicate that the adsorption reaction takes place spontaneously, ΔHo of 0.8130 indicates an endothermic reaction, and ΔSo of 4.1888 indicates an increase in the randomness of the adsorption process at the adsorbent interface and lead during adsorption.

A strategy for deep removal of Cu from Ni anolyte based on the ion-exchange method

The sulfide precipitation method has been one of the major strategies used for the removal of Cu from the Ni anolyte. However, the high cost and short shelf-life of the Cu removal agents have consistently posed problems in the practical industrial use of the Ni anolyte purification process. In the present study, a new method for removing Cu from Ni anolyte based on ion exchange is proposed to address the drawbacks of the current sulfide precipitation method. Through isothermal adsorption curve analysis, thermodynamic studies, kinetic studies and cross-sectional SEM-EDS analyses, it was found that the selectivity difference of D850 resin to Cu2+ and Ni2+ is dependent on iminodiacetic acid forming a triple bond with Cu2+ while forming a double bond with Ni2+ in the removal of Cu from a Ni anolyte. The resin dynamic adsorption experiments showed that the fixed-bed ion exchange process is quite similar to the cascade solvent extraction process. The investigations into resin regeneration found that the desorption of Cu2+ and Ni2+ was adequately completed for static desorption when the desorbent concentration was than more 1 mol/L for 60 min. The experiments on D850 resin desorption showed that the desorption equilibrium time, desorbent concentration, and desorption temperature were key factors affecting the desorption of Cu2+ and Ni2+. The dynamic desorption process revealed that a high concentration of hydrochloric acid and a high flow rate could accelerate the desorption process, concentrating the outflow peak and facilitating the collection of Cu2+ and Ni2+. This Cu removal method based on resin ion exchange utilizes the different characteristics of iminodiacetic acid adsorbing Cu and Ni to achieve efficient Cu removal from the Ni anolyte and its recycling. This method is superior to the current method due to its high selectivity, fast adsorption, high desorption rate, and high Cu–Ni ratio of the desorption solution.

Isotherm Adsorption Kinetics Study of Methylene Blue on Reduced Graphene Oxide from <i>Borassus flabelifer </i>L Fiber

Isotherm Adsorption Kinetics Study of Methylene Blue on Reduced Graphene Oxide from <i>Borassus flabelifer </i>L Fiber

Synthesis of Zr-based metal-organic framework/MWCNTs composite for adsorption of enrofloxacin from aqueous solution

Enrofloxacin, as one of the specialized fluoroquinolone antibiotics, has become a typical “emerging” pollutant in aqueous environment because of its great stability and resistance to degradation. Therefore, it is important to find an effective method to remove it from aqueous solution. In order to check the presence of synergies between UiO-66 and MWCNTs on removal of enrofloxacin from aqueous solution, a composite material, known as UiO-66/MWCNTs, was synthesized by using hydrothermal method. The physical and chemical properties of the synthesized composite were characterized by using methods such as XRD, N2 adsorption–desorption, FT-IR, SEM and XPS. The results revealed that UiO-66/MWCNTs has large specific surface area (837.56 m2/g) and high porosity, as well as rich functional groups (C = C, –OH, –COOH). Factors such as contact time, initial concentration, temperature, pH, and ionic strength were considered to test the adsorption performance of pristine MWCNTs, pristine UiO-66 and UiO-66/MWCNTs composite for enrofloxacin. The results showed that the UiO-66/MWCNTs composite has a higher adsorption capacity at basic condition and the maximum adsorption capacities of enrofloxacin on composite was improved from 67.8 mg/g for MWCNTs and 92.8 mg/g for UiO-66 to 134.2 mg/g due to its higher adsorption active sites. The adsorption kinetics studies implied that the adsorption of enrofloxacin onto the studied sorbents involves in physio-chemical interactions and is an intra-particle diffusion controlling process. The isothermal experimental data were compatible with both Langmuir and Freundlich models, suggesting heterogeneous adsorption was the dominant during the course of adsorption. Additionally, the thermodynamic parameters indicated that the adsorption of enrofloxacin on UiO-66/MWCNTs was spontaneous and endothermic in nature. Finally, in combination with XPS analysis, the adsorption mechanism of enrofloxacin on UiO-66/MWCNTs was clarified to be the synergetic effect of chemical adsorption, hydrogen bond and π-π interaction. This work provides a new strategy for the removal of drugs from aqueous environment.

Large particle size boosting the engineering application potential of functional biochar in ammonia nitrogen and phosphorus removal from biogas slurry

The practical engineering application of biochar has been hindered by limitations in the fabrication process and parameters used. This study aimed to overcome these limitations by preparing layered double hydroxides (LDH)-anchored biochar using larger particle size biomass. We analyzed the physicochemical properties of the functional biochar and conducted adsorption studies on wastewater-biogas slurry. Based on elemental analysis and static adsorption experiments, the biochar fabricated from powdered biomass had higher activator utilization and maximum adsorption capacity than biochar from larger particle size biomass. However, based on BET analysis and results from adsorption kinetics studies, the biochar derived from larger particle biomass exhibited outstanding surface properties and exceptional adsorption efficiency. Notably, in dynamic adsorption experiments, the LDH-anchored biochar derived from larger particle size biomass performed exceptionally well in a fixed bed column at high liquid flow rates (15 mL min−1). Based on the fitting results of mass transfer kinetics, we observed that the adsorption capacity of ammonia nitrogen remained relatively constant, while phosphorus adsorption increased at high flow rates compared to low flow rates. Scale-up design results showed that the biochar fixed bed column could handle a large volume (108 m3) of biogas slurry per day, recovering significant amounts of ammonia nitrogen (188.6 kg) and phosphorus (1.2 kg). These findings highlight the potential of functional biochar derived from larger particle size biomass for engineering applications in wastewater treatment.

TD-DFT calculation, equilibrium and kinetic adsorption study of removal of rose bengal dye by poly vinyl alcohol as a synthetic polymer adsorbent hybrid blend

Spectrophotometric study of the efficacy of the synthetic polymer such as polyvinyl alcohol in the removal of the dye Rose Bengal (RO) was examined. Different contact times, starting dye concentrations, adsorbent doses, dye solution temperatures, and pH values were tested. Density functional theory (DFT) with functional B3LYP and Hartree-Fock (HF) were used to investigate the optimal geometries, vibrational wavenumbers, vibrational band intensities, and atomic charges of 9VC. The researchers contrasted theoretical predictions for the basic vibrational modes with actual measurements. Using the functional B3LYP of DFT, we analyzed the hybrid organic dye (PVA+RO)HB such as the shape of geometry, electronic configuration, the capacity of polarizability, and second-order hyperpolarizability. The time-dependent density functional theory (TD- DFT), linked to a variety of hybrid functionals, was used in order to conduct research on the electronic absorption spectrum. Good agreement was found between the correlation coefficient values obtained from the Langmuir and Freundlich isotherm models, which were used to characterize the adsorption equilibrium. Pseudo-first-order kinetics was the best fit for the data on RO adsorption onto PVA. The values of enthalpy change and free energy change are negative and these confirm that our study concluded the exothermic and adsorption mechanism was spontaneous, respectively. The adsorption capacity was found to increase with increasing temperature. So, the kinetic parameters were evaluated from the temperature dependence of the adsorption capacity using the method of least squares.

Defluoridation of Water by Biowaste Material – A Study of Adsorption Kinetics and Isotherms

Human beings experience adversative effects due to the large fluoride concentrations present in potable water. Because of the low cost and simple operation, the extensively acknowledged process is adsorption. The objective of this study is to investigate the performance of some of the prepared carbons from bio-waste materials viz., Citrus limon, Citrus nobilis, Pithecellobium dulce, and Bombax malabaricum sheaths in defluoridation. Initial concentration, particle size, agitation time, adsorbent dose, and pH were the different parameters chosen to study their effect on adsorption. Studied the adsorption kinetics. Further suitability to adsorption isotherms was reviewed.

Nanoparticle-assisted removal of EBT dye from textile wastewater: Towards sustainable Green gram seedling cultivation

Background: Wastewater refers to water of substandard quality that originates from urban and suburban regions. The water in question is used for cultivation in regions where there is a limited water supply for agricultural activities. The utilisation of marginal quality water for farming spans about 20 million hectares of land globally, with around 10% of the global population consuming food crops that have been irrigated with this kind of water. Methods: The CuONPs wassynthesizedby a chemical method, followed by their characterization using many methods including UV-Vis spect., FTIR, DLS, XRD, and SEM.The photocatalytic degradation of EBT dye and its adsorption kinetic studies were performed. Furthermore, impact of CuONPs, and wastewater on green gram seedlings under in-vitro conditions.Findings: The chemical methods effectively synthesized CuONPs as well as under ideal phytocatalytic condition CuONPsdegraded the EBT dye up to 51.09% in 5h of treatment.The inclusion of CuONPsat a dosage of 100 mg L−1 in the wastewater proceeded in a notable improvement in the green gram seed germination by 50%, and notable biometric profile as well as essential biomolecule (chlorophyll a&b, total soluble phenolics, and lycopene) profiles.

Fabrication of Highly Efficient Fe3O4/SSIP/GO Composite Films for Removal of Methylene Blue Dye

In this paper, we report the preparation of a new Fe3O4/SSIP/GO composite film for the purification of methylene blue dye from solution media. The preparation process of composite film was carried out to improve the interaction between the inner part of the sunflower stalk (SSIP) and surface matrix using magnetite/Graphene Oxide (Fe3O4/GO) minerals at weight ratios (0.2/4/0.2:w/w/w). The characterizations of as-developed Fe3O4/SSIP/GO composite film was successfully carried out by some advanced techniques such as FT-IR, SEM, and TGA analyses. Adsorption kinetic studies were evaluated in three different aspects as a pseudo-first-order model, pseudo-second-order model, and intraparticle diffusion-type model. Based on the R2 results, it was seen that the Pseudo-second order kinetic model (0.999) acted more harmoniously than the pseudo-first-order (0.960) and intra-particle diffusion technique models (0.974). In the light of these findings, it can be said that the prepared Fe3O4/SSIP/GO composite film used for removal of methylene blue dye can be considered as a promising material

Kinetic and Isothermal Study for Adsorption of Lanthanum on Modified Activated Carbon

Kinetic and Isothermal Study for Adsorption of Lanthanum on Modified Activated Carbon

Adsorption equilibrium and kinetics studies of crystal violet adsorbed by anionic polymer brush functionalized mesoporous silica nanoparticles

The removal of crystal violet (CV) dye from an aqueous solution has been investigated using anionic poly(potassium 3-sulfopropyl methacrylate) (PKSPMA) brushes grafted on mesoporous silica nanoparticles (MSNPs). Fourier-transform infrared spectroscopy (FTIR) and transmission electron microscopy (TEM) were used to characterize PKSPMA brushes modified MSNPs (PKSPMA@MSNPs). Surface-modified MSNPs were almost spherical shapes with sizes ranging between 190 nm and 340 nm with an average pore size of ca. 5. The adsorption process of the CV was investigated under various of testing conditions, including pH, contact duration and initial dye concentration. The maximum loading of CV onto PKSPMA@MSNPs was observed at pH 3, with approximately 91% adsorption efficiency at a concentration of 100 ppm. The removal of CV onto PKSPMA@MSNPs was best described by the Langmuir isotherm, with a maximum monolayer adsorption capacity (qmax) of 128.37 mg g−1. The kinetics of the adsorption process were best described by the pseudo-second-order model.

Powdered activated carbon adsorbent for eosin Y removal: modeling of adsorption isotherm data, thermodynamic and kinetic studies

Abstract An investigation was conducted to examine the adsorption of eosin Y (EY) from aqueous solution using Powdered Activated Charcoal (PAC) obtained from Biochem Chemopharma (Quebec, Canada) with a surface area of 270 mg/g using the methylene blue method. The adsorption experiments showed that a contact time of 60 min resulted in a high removal efficiency of 98.25 % for EY at a concentration of 10 ppm. The study also offered insights into the effectiveness of different treatment processes and described the main physicochemical processes involved. Various parameters such as adsorbent dosage, contact time, substrate concentration, and pH were evaluated, and the data were analyzed using Freundlich, Langmuir, and Temkin isotherms. The study found that the pseudo-second-order kinetic model provided a better fit to the experimental data compared to the pseudo-first-order model. To optimize the process parameters and enhance overall efficiency, contour plots were employed in the experimental design, considering variables such as adsorbent dosage, contact time, and pH levels. These plots visually represented the relationship between the variables and the removal efficiency of EY, enabling the identification of optimal operating conditions. The investigation’s findings contribute valuable insights into the adsorption of EY using PAC and offer practical implications for improving the efficiency of EY removal in various applications. The use of contour plots in experimental design was highlighted as a crucial tool for refining adsorption process parameters.

Swift Removal of the Heavy Metals Cadmium and Lead from an Aqueous Solution by a CAN-Zeolite Synthesized from Natural Clay

CAN-zeolite was synthesized with a high purity from natural kaolinite via alkali fusion by hydrothermal treatment at a pressure of 1 kbar H2O. It was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), infrared spectroscopy and nitrogen adsorption at 77 K. The results show that after AK hydrothermal treatment (under specific conditions), the SBET increases from 5.8 m2g−1 to 30.07 m2g−1 which is six times greater. The AK which was a non-porous or macroporous solid (the nitrogen adsorption/desorption of AK is of type II) became mesoporous (N2 adsorption–desorption isotherms exhibit typical hysteresis of type IV) with a pore size of 5.9 Å. XRD of AK shows the presence of quartz (Q) as impurities, and illite and kaolinite as major fractions; after hydrothermal treatment, the XRD diffractogram shows only fine pics related to CAN-zeolite (with a good crystallinity), confirming the success of the synthesized process. These results suggest that the synthesized CAN-zeolite has the potential to be tested in the removal of heavy metals from waste water as part of a remediation process. Batch reactors were used to evaluate the adsorption isotherms and kinetic studies of heavy metals, cadmium, and lead, by natural kaolinite clay (AK) and synthesized cancrinite zeolite (CAN-zeolite). The results show that the adsorption kinetics of the bivalent heavy metals cadmium and lead are extremely fast with either AK or CAN-zeolite. Equilibrium was reached within 2 min. Adsorption isotherms show that the synthesized CAN-zeolite has a higher adsorption capacity; the retention capacity of lead and cadmium was three times greater than that presented by the natural clay mineral. According to the findings, CAN-zeolite has a higher affinity for PbII (192 mg/g) compared to CdII (68 mg/g). The negative reactive surface sites interacting with these cationic heavy metals resulted in a higher amount of heavy metals adsorption than the cation exchange capacity (CEC). The adsorption information was analyzed using the Langmuir and Freundlich equations. The Langmuir model provided a good fit to the equilibrium data, indicating a monolayer adsorption mechanism.