Equilibrium Sorption Capacity Research Articles

Electrospun nanofibrous membranes based on fluorine-free polyimide for swift oil spill cleanup and emulsion separation

The urgent need to mitigate environmental damage caused by oil and organic pollutants in oil production industries and spill accidents necessitates effective removal methods. This study introduces novel nanofibrous membranes composed of fluorine-free polyimide, which was formed by electrospinning of BPADA-TrMPD, produced by polycondensation reaction in one-step and at high temperature using 4,4′-(4,4′-isopropylidenediphenoxy)bis-(phthalic anhydride) (BPADA) and 2,4,6-trimethyl-m-phenylenediamine (TrMPD). The resulting membranes exhibited a hydrophobic nature with a water contact angle of 114° and an oil contact angle of ∼ 0°. The adsorption performance of the nanofibers was explored using Saudi crude oil and non-polar organic solvents (i.e., n-hexane and dodecane). The developed membranes exhibited a crude oil uptake ranging from 35 to 60 g g−1 and demonstrated rapid removal capabilities, reaching equilibrium sorption capacity within a few minutes for crude oil. Moreover, these membranes displayed remarkable flux of 1991, 1508, and 206 L m−2h−1 for dodecane, n-hexane, and crude oil, respectively. The capability of the fluorine-free mats designed for oil spill cleanup was validated through its application in treating actual samples. The durability and recyclability of the membranes were showcased by regenerating them through mechanical treatment.

Chitosan/Poly(maleic acid-alt-vinyl acetate) Hydrogel Beads for the Removal of Cu2+ from Aqueous Solution.

Covalent cross-linked hydrogels based on chitosan and poly(maleic acid-alt-vinyl acetate) were prepared as spherical beads. The structural modifications of the beads during the preparation steps (dropping in liquid nitrogen and lyophilization, thermal treatment, washing with water, and treatment with NaOH) were monitored by FT-IR spectroscopy. The hydrogel beads have a porous inner structure, as shown by SEM microscopy; moreover, they are stable in acidic and basic pH due to the covalent crosslinking. The swelling degree is strongly influenced by the pH since the beads possess ionizable amine and carboxylic groups. The binding capacity for Cu2+ ions was examined in batch mode as a function of sorbent composition, pH, contact time, and the initial concentration of Cu2+. The kinetic data were well-fitted with the pseudo-second-order kinetic, while the sorption equilibrium data were better fitted with Langmuir and Sips isotherms. The maximum equilibrium sorption capacity was higher for the beads obtained with a 3:1 molar ratio between the maleic copolymer and chitosan (142.4 mg Cu2+ g-1), compared with the beads obtained using a 1:1 molar ratio (103.7 mg Cu2+ g-1). The beads show a high degree of reusability since no notable decrease in the sorption capacity was observed after five consecutive sorption/desorption cycles.

Effect of polyvinylpyrrolidone and lithium chloride composite desiccant-coated heat exchangers on dehumidification studies

Cooling systems are necessities that remain energy intensive, particularly in tropical regions with elevated humidities and temperatures. Conventional vapor-compression air-conditioners are often inefficient because the sensible and latent heat loads are intrinsically coupled. To realize more energy-efficient cooling, solid desiccant-coated devices can be introduced to mitigate the latent heat load. Among such devices, desiccant-coated heat exchangers (DCHEs) are attractive for enabling nearly isothermal dehumidification. Hence, desiccants with high sorption capacity and rapid kinetics are essential. Solid polymeric desiccants are well-positioned to meet these requirements but comprehensive studies on the dehumidification performance of solid polymeric desiccant-coated heat exchangers are currently lacking. In this study, we investigated the potential of polyvinylpyrrolidone (PVP) and lithium chloride (LiCl) composites as desiccant materials at both material and system levels in terms of gravimetric water uptake. Specifically, LiCl is a hygroscopic salt bound by the moisture-sorbing PVP matrix. This work also demonstrates how the Elovich model accurately predicted the PVP-LiCl composite’s sorption kinetics. The results show that the optimum PVP-LiCl composite ratio is 66.7 wt%, with an equilibrium sorption capacity of 280 % at 75 % RH and 25 °C, compared to 29 % for silica gel under the same condition. With much superior sorption kinetics and capacity, the PVP-LiCl-coated prototype heat exchanger demonstrated a moisture removal capacity eight times higher than a silica gel-coated one under dynamic flow towards energy savings in air-conditioning systems.

Non-derivatizing solvent assisted waste-derived cellulose/ MOF composite porous matrix for efficient metal ion removal: comprehensive analysis of batch and continuous packed-bed column sorption studies.

The use of metal-organic frameworks (MOFs) for wastewater treatment in continuous operation is a major challenge. To address this, the present study demonstrates the eco-friendly and economic synthesis of Ca-MOF immobilized cellulose beads (Ca-MOF-CB) derived from paper waste. The synthesized Ca-MOF-CB were characterized using standard analytical techniques. Batch sorption studies were performed to check the effect of cellulose composition (wt%), Ca-MOF loading, contact time, and initial metal ion (Pb2+, Cd2+, and Cu2+) concentration. Ca-MOF-CB beads exhibited outstanding equilibrium sorption capacities for Pb2+, Cd2+, and Cu2+, with estimated values of 281.22 ± 7.8, 104.01 ± 10.58, and 114.21 ± 9.68 mg g-1, respectively. Different non-linear isotherms and kinetic models were applied which confirmed the spontaneous, endothermic reactions for the physisorption of Pb2+, Cd2+, and Cu2+. Based on the highest equilibrium sorption capacity for Pb2+ ion, in-depth parametric column studies were conducted in an indigenously developed packed-bed column set-up. The effect of packed-bed height (10 and 20 cm), inlet flow rate (5 and 10 mL min-1), and inlet Pb2+ ion concentration (200, 300, and 500 mg L-1) were studied. The breakthrough curves obtained at different operating conditions were fitted with the empirical models viz. the bed depth service time (BDST), Yoon-Nelson, Thomas, and Yan to estimate the column design parameters. In order to determine the financial implications at large-scale industrial operations, an affordable synthesis cost of 1 kg of Ca-MOF-CB was estimated. Conclusively, the present study showed the feasibility of the developed Ca-MOF-CB for the continuous removal of metal ions at an industrial scale.

Highly selective separation of plutonium using a mono-amide-based supported liquid membrane

ABSTRACT A monoamaide-functionalized supported liquid membrane was developed and employed for efficient and selective solid phase separation of Pu(IV). The membrane was prepared in a simple, one-pot process and was characterized for its homogeneity, stability and hydrophobicity. Various membrane parameters like sorption efficiency, sorption kinetics, sorption isotherm and equilibrium uptake capacity were studied for Pu(IV) in nitric acid medium. Langmuir and Freundlich isotherm models were employed for understanding the sorption mechanism of the membrane. Lagergren first-order kinetics and pseudo-second-order kinetics were applied to understand the plutonium sorption kinetics. The equilibrium sorption capacity of the membrane was found to be 27.18 mg g−1and the sorption kinetics followed a pseudo-second-order reaction with rate constants of 1.129 g mg−1 min−1 for Pu(IV). Stripping of Pu from the membrane was also studied to check the regeneration and reusability of the supported liquid membrane. The membrane was found to be very selective toward Pu(IV) in 4 M HNO3 medium, with separation factors 42 and 75 with respect to Am(III) and U(VI), respectively.

Synthesis, characterization, and application of hydroxyapatite grafted over pristine charcoal /activated charcoal for removal of pb2+ ions from aqueous solution

Hydroxyapatite (HAP) is one of the major components found in bones and teeth and has outstanding biocompatibility. Hydroxyapatite is a possible sorbent for heavy metals in contaminated water attributable to its high adsorption capabilities and solubility of water very low. However, pure hydroxyapatite is very difficult to use because it exists in the form of white power and also is too much costly. The above difficulties were overcome by the synthesis and characterization of hydroxyapatite grafted over Pristine charcoal/ activated charcoal for the expulsion of lead ions from aqueous solutions by the simple hydrothermal process at different temperatures like 120 °C and 150 °C. The result reveals that rod-like HAP nanocrystals with a range of 22––62 nm, are impregnated over charcoal. Characterization of synthesized hydroxyapatite samples by using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), Field emission scanning electron microscopy (FESEM), and Energy-dispersive X-ray spectroscopy (EDX) methods. To investigate adsorbent for removal of Pb2+ from an aqueous solution of Pb (NO3)2, and to vary the adsorbent dosage to evaluate its influence on the adsorption efficiency. The observed that synthesis of HT-CH at 120 °C gives the best result, UV Analysis for the calculation of equilibrium sorption capacity of HT-CH120 and HT-ACH120 on the adsorption of Pb2+ ion is carried out by Lambert-Beer law. The equilibrium sorption capacity of HT-CH120 is 76.13 mg/gm while the equilibrium sorption capacity of HT-ACH120 is 15.8 mg/gm.

Synthesis, Characterization and Potential Application of Functionalised Binary Metallic Sulphide for Water Reclamation

The present paper highlights the synthesis of novel Citric acid functionalized-Nickel-Cobalt-Sulphide nanoparticles, abbreviated as Ni-Co-S@Ct, via simple co-precipitation method. The prepared nanoparticles have been characterized using several analytical techniques, like XRD, HR-TEM, TGA, HR-SEM, FT-IR, XPS and BET and zeta potential measurements. The prepared Ni-Co-S@Ct nanoparticles have been investigated for the adsorptive removal of different types of pollutants, namely, cationic and anionic dyes, and arsenic ions and interestingly all of these pollutants were removed with high efficiency. The equilibrium sorption capacity of Ni-Co-S@Ct has been found 90.91 mg/g for Methylene blue, 232.55 mg/g for Crystal violet, 357.14 mg/g for Nile blue, 142.9 mg/g for Congo red, 1111 mg/g for As(III) and 2000 mg/g for As(V). The sorption data for these pollutants fitted well to Freundlich and Temkin isotherms which showed the attachment of these ions/molecules to the specific sites at Ni-Co-S@Ct heterogeneous surface. The kinetics of sorption process was explained using the pseudo-second order model which suggested pollutant ion attachment at specific sites at the surface of Ni-Co-S@Ct. The FT-IR and Zeta potential analysis led to the conclusion that electrostatic interaction and metal complexation might be the prominent pathways adopted by the Ni-Co-S@Ct for the sorption of dyes and arsenic ions. The nanomaterials was further investigated for the removal of dyes from the mixture of dyes and the results have been quite promising as the material was found effective for elimination of four dyes simultaneously. Therefore, the high adsorption capacity, low-cost and facile synthesis, takes Ni-Co-S@Ct a step ahead in environmental remediation and wastewater treatment technology.

Design and Preparation of Magnetically-Oriented Poly(styr-co-MMA)-3MPS Capped Fe(ZnO) Hybrid Microspheres for Ion Exchange Removal of Toxic Pollutants from Wastewater

In this work, polymeric microspheres derived from polystyrene-co-methyl methacrylate embedded with magnetic ZnO nanoparticles (poly(styrene-co-MMA)-3MPS-Fe (ZnO)) were synthesized using the suspension polymerization method. The surfaces of polymeric Fe(ZnO) microspheres were improved by functionalization with amino and sulphonate groups. The physicochemical analysis indicated a large number of positively charged (anion exchange) groups (91 mmol/g) on the amine-modified polymeric microsphere (MFZPI) and a large number of negatively charged (cation exchange) groups (90 mmol/g) on the sulphonate-modified polymeric microsphere (SMFZPI)—revealing ambivalent character of obtained sorbent. The characterization of the synthesized compounds using various analytical techniques such as TGA, FTIR, XRD, SEM/EDX, UV-VIS and VSM indicated that synthesized microspheres were thermally stable, semi-crystalline in structure with hollow irregular morphology, optically active in UV region and slightly magnetic in nature. Due to the introduction of groups having ion exchange properties, these modified poly(styrene-co-MMA)-3MPS-Fe(ZnO) microspheres were used for the ion exchange sorptive removal of Cr(III) and fluorescein from aqueous matrix. The equilibrium sorption capacity of Cr(III) was 16.79 mg/g whereas of fluorescein was 12.03 mg/g under optimized conditions. Therefore, SMFZPI was found to be a promising sorbent for both cationic heavy metals and anionic dyes due to the presence of both acidic and basic groups. The mathematical modelling revealed that the sorption phenomenon followed pseudo-second-order kinetics with Freundlich equilibrium isotherm, indicating multilayer chemisorption of the pollutants on the synthesized ion exchange sorbents. This work establishes the utilization of polymeric magnetic ZnO-based ion exchange sorbents to effectively remove harmful toxins from wastewater.

Investigating bisulfide sorption onto bentonite through laboratory batch experiments

Bentonite clay is a key part of the engineered barrier system of the deep geological repositories (DGRs), designed by many nuclear nations worldwide to safely house the used nuclear fuel. However, the copper coated used fuel containers (UFCs) may undergo corrosion due to bisulfide (HS−) transport through the bentonite towards the containers. Understanding the sorption behaviour of HS− is therefore critical in understanding the HS− transport dynamics and in assessing the long-term safety of the DGR. As such, this study investigated HS− sorption onto bentonite, through laboratory batch experiments and microscopic/spectroscopic analyses, under the influence of various experimental conditions, such as contact time (1–120 h), temperature (10–40 °C), liquid to solid mass ratios (L:S) (100–1000), initial HS− concentration (1–6 mg L−1). The study results indicated that HS− sorption onto bentonite occurred faster and the equilibrium sorption capacity increased (by 3%) with increasing temperature (from 10 °C to 40 °C). Several established kinetic and isotherm models were applied to the experimental data to provide insight into the key processes driving HS− sorption onto bentonite. The desorption test results indicated that HS− was irreversibly sorbed on bentonite. The surface analyses of the bentonite test samples were conducted using scanning electron microscopy along with energy dispersive spectroscopy. These results suggested that the sorption might have occurred due to chemical reactions of HS− with the iron present in bentonite and subsequent formation of iron monosulfide (FeS). The findings of this study provided critical information to better understand the underlying sorption mechanism of HS− on bentonite, which can reduce HS− transport in the DGR.

Development and characterization of DTMS treated nettle fiber nonwovens for oil spill removal applications

In this work, nonwoven oil sorbent from nettle fiber was developed by changing the hydrophilic surface of nettle fiber to a hydrophobic surface by dodecycltrimethoxysialne (DTMS) treatment. Change in the surface structure of the fiber due to DTMS treatment was confirmed by SEM analysis. Fourier transform infrared analyses showed clear evidence of successful incorporation of DTMS on nettle fiber. The oil sorption capacities of diesel oil and crude oil were 31.39 and 41.89 g/g, respectively, which were found to be considerably higher than commercial oil sorbents. The pseudo first order and pseudo second order kinetic equations were employed to obtain the sorption rate constants and equilibrium sorption capacity. The results showed that the process fits the pseudo second-order kinetic model better for oil sorption than the pseudo first-order kinetic model. Also, the sorption capacities of the unmodified and modified samples were estimated by analyzing the isotherm data using Langmuir and Freundlich adsorption isotherm models. The results show that fitting via the Langmuir isotherm model produced a higher correlation coefficient than fitting via the Freundlich isotherm model. DTMS treated nettle nonwoven fabrics also showed good buoyancy characteristics under both static and dynamic conditions. Due to high oil sorption ability, reusability, and environmental responsiveness, the developed nonwoven oil sorbent can be considered as a potential substitute for organic synthetic fiber for oil spill removal applications.

Developing a Chromatographic 99mTc Generator Based on Mesoporous Alumina for Industrial Radiotracer Applications: A Potential New Generation Sorbent for Using Low-Specific-Activity 99Mo.

The commercial low-pressure column chromatographic 99Mo/99mTc generator represents a reliable source of onsite, ready-to-use 99mTc for industrial applications. These generators use fission-produced 99Mo of high specific activity, posing serious production challenges and raising proliferation concerns. Therefore, many concepts are aimed at using low-specific-activity (LSA) 99Mo. Nonetheless, the main roadblock is the low sorption capacity of the used alumina (Al2O3). This study investigates the feasibility of using commercial alumina incorporated with LSA 99Mo to develop a useful 99Mo/99mTc generator for industrial radiotracer applications. First, the adsorption profiles of some commercial alumina sorbents for LSA 99Mo were tested under different experimental conditions. Then, the potential materials to develop a 99Mo/99mTc generator were selected and evaluated regarding elution yield of 99mTc and purity. Among the sorbents investigated in this study, mesoporous alumina (SA-517747) presented a unique sorption-elution profile. It demonstrated a high equilibrium and dynamic sorption capacity of 148 ± 8 and 108 ± 6 mg Mo/g. Furthermore, 99mTc was eluted with high yield and adequate chemical, radiochemical, and radionuclidic purity. Therefore, this approach provides an efficient and cost-effective way to supply onsite 99mTc for radiotracer applications independent of fission-produced 99Mo technology.

Kinetic Study of Malathion Biosorption Using Dry Cells of an Isolated Bacillus sp. S14

Pesticides Pollutants are a major ecological issue because they kill organisms that are not their intended targets. Even in trace amounts, their diversity, toxicity, and durability are harmful to natural systems. High levels of malathion in the air, water, or food can make breathing difficult, tighten the chest, cause nausea, cramps, diarrhoea, watery eyes, impaired vision, salivation, perspiration, headaches, and even cause death. Two kinetic models—pseudo-1st- and pseudo-2nd order were used to examine the sorption isotherm of malathion onto Bacillus sp. S14, and they were fitted using non-linear regression. The pseudo-1st order model was found to be the best model by statistical analysis based on root-mean-square error (RMSE), adjusted coefficient of determination (adjR2), bias factor (BF), accuracy factor (AF), corrected AICc (Akaike Information Criterion), Bayesian information criterion (BIC), and Hannan-Quinn information criterion (HQC). A kinetic study employing the pseudo-1st order model at 150 PPM yielded an equilibrium sorption capacity qe of 4.19 mg/g (95% confidence interval from 4.137448 to 4.257148) and a pseudo-1st-order rate constant, k1 of 0.53. (95 percent confidence interval from 0.510371 to 0.559508). Further analysis is required to give evidence for the chemisorption mechanism commonly associated with this kinetic.

Batch and continuous processes for the removal of Al3+ and Fe2+ from aqueous effluents using spent coffee ground

Due to the intense industrialization of the modern society, severe contamination of water by dangerous metal ions has become a major problem. The use of plant-derived biosorbents has been proposed in different studies in reason of their good performance and marginal cost. The proposal of this study was to evaluate the use of spent coffee ground (SCG) for the removal of metal ions from aqueous effluents. The batch process showed removal efficiencies equal to 92.4% for Al3+ and 85.9% for Fe2+, and the continuous process showed removal efficiencies equal to 97.2% for Al3+ and 96.2% for Fe2+. These two processes were compared using Freundlich and Langmuir models, and Langmuir-3 model showed the best adequacy for all processes indicating to be favorable (0.12 ≤ RL ≤ 0.59), with equilibrium sorption capacities between 1.79 and 4.21 mg/g SCG. Kinetic evaluations suggested that these two processes follow a pseudo-second order model for both ions, with thermodynamically favorable characteristics. All data indicated that this biosorbent has a good potential to be used for the removal of metal ions from contaminated aqueous effluents.

Physico-chemical and adsorption study of hydrothermally treated zeolite A and FAU-type zeolite X prepared from LD (Linz–Donawitz) slag of the steel industry

ABSTRACT Sodium-rich zeolite A and zeolite X (FAU-type) samples were synthesised from LD-slag via fusion-assisted hydrothermal treatment. The physicochemical and thermal stability of the prepared samples were examined with the help of various characterisation techniques, namely, Fourier Transform Infrared (FTIR) spectroscopy, X-ray diffraction (XRD) and thermogravimetric analysis (TGA) analysis at three different pH conditions and treatment time. Moreover, the sustainability of the crystalline phase and the corresponding zeolite network was evaluated from XRD, FTIR, TGA and Field-Emission Scanning Electron Microscopy (FESEM) analysis. Zeolite A depicts a unique cubical structure and is thermally more stable as compared to zeolite type-X. Also, zeolite A showed the highest dye removal efficiency of 98.13%, as compared to 94.47% for zeolite X, along with equilibrium sorption capacities of 25.30 and 23.57 mg g−1, respectively. In addition, the study proposes that both the synthesised adsorbents are effective and economically sustainable for cationic methylene blue adsorption. Furthermore, methylene blue adsorption was regulated by a multistage diffusion process that agreed with a pseudo-second-order kinetic model (R2 = 0.999 and 0.996 for A- and X-type zeolites). The Langmuir isotherm model best suited the equilibrium data, with monolayer adsorption capacities of 20 and 25.40 mg g−1, respectively.

Grafted mesoporous silicas for radionuclide uptake: Radiolytic stability under electron irradiation

Materials developed for radionuclide adsorption need to resist harsh conditions, i.e. be robust against ionizing radiation. In this work, we evaluated the degradation of mesoporous silicas (SBA-15) grafted with hydroxypiridinone, acetamide phosphonate and propionamide phosphonate ligands under electron irradiation. The ligands contained amide and/or phosphinic acid functional groups, which made them able to bind to actinides. Degradation of the grafted ligand was assessed by identifying and quantifying the gas produced under irradiation using gas chromatography, as well as characterizing the grafted ligands before and after irradiation by means of FT-IR, XPS and TGA techniques. Irradiation led to the degradation of amide functional groups and to the production of amine and carboxylic acid groups. Corresponding reaction mechanisms were proposed. The sorption behavior of the grafted SBA-15 materials for thorium was also studied. SBA-15 materials grafted with acetamide phosphonate and propionamide phosphonate ligands were shown to be able to adsorb thorium. The propionamide phosphate ligand was the most efficient, with an equilibrium sorption capacity of 95 mg g−1. This capacity remained stable up to a 1 MGy irradiation dose and underwent a 20% decrease after 4 MGy of irradiation. Therefore, this material is potentially interesting for the treatment of liquid outflows contaminated by actinides produced in nuclear facilities.

Biosorption of heavy metals: Transferability between batch and column studies

The design of an industrial water treatment system using sorption is based on laboratory column tests. To verify the applicability of a column sorption system at industrial scale, it is necessary to determine the system's breakthrough time (BT) in a laboratory setting. In a laboratory column set-up, BT is referred to as the time taken by the adsorbate to appear at column outlet for the first time. This is when the mass transfer zone (MTZ), where the equilibrium sorption occurs, reaches the end of the sorbent bed. However, such laboratory set-up requires significant resources including laboratory space, time and multiple trials, which is the opposite to the batch experimental approach that is commonly used to assess efficiency of sorbents. This study identified batch sorption parameters that can be used to determine BT for a column sorption setting for three toxic heavy metals commonly found in industrial wastewater, namely, Pb2+, Cd2+ and Cu2+. The study conducted a comprehensive evaluation of the relationships between column BT and its key influential factors, namely, equilibrium sorption capacity (qe), pseudo second-order kinetic rate constant (k2) and initial sorption rate (h). The results revealed that BT can be better estimated using h compared to qe and k2. As such, a batch experiment which is more resource efficient could be undertaken for an initial estimation of the experimental BT of a column system. Moreover, a simulation model developed to replicate column sorption could demonstrate the behaviour of the breakthrough curve, which is a key to the selection and assessment of the performance of a sorbent in an adsorbent column. The estimation errors in qe and k2 were found to influence the simulation outcomes. Hence, it is necessary to further investigate the other factors that can potentially influence sorption behaviour.

Kinetic Analysis of the Adsorption of Ethyl Violet onto Graphene Oxide Sheets Integrated with Gold Nanoparticles

An example of biosorption is when the sorbent is made from a biodegradable material. Biosorption is now being seen as a simple, cost-effective, and environmentally acceptable alternative to traditional pollution treatment methods. Bioremediation is one of the branches of bioremediation that is used to minimise pollution in the context of incorrect dye waste disposal. The sorption isotherm of Ethyl Violet onto graphene oxide were analyzed using three models—pseudo-1st, pseudo-2nd and Elovich, and fitted using non-linear regression. Statistical analysis based on root-mean-square error (RMSE), adjusted coefficient of determination (adjR2), bias factor (BF), accuracy factor (AF), corrected AICc (Akaike Information Criterion), Bayesian Information Criterion (BIC) and Hannan–Quinn information criterion (HQC) that showed that the pseudo-second-order model was the best which was the same finding from the original published work. The calculated evidence ratio was 11 with an AICc probability value of 0.91 indicating that the best model was at least 11 times better than the nearest best model, which was pseudo-1st. Further analysis is needed to provide proof for the mechanism usually tied to this kinetic. Nonlinear regression analysis using the pseudo-2nd order model for the highest concentration tested, which was 10 mM, gave values of equilibrium sorption capacity qe of 30.928 mg/g (95% confidence interval from 29.328 to 32.527) and a value of the pseudo-2nd-order rate constant, k2 of 0.020 (95% confidence interval from 0.011 to 0.028).

Kinetic Analysis of the Adsorption of Cibacron Blue onto Bean Peel

Biosorption is a kind of sorption technology in which the sorbent is derived from a biological source. At the moment, biosorption is seen as a simple, cost-effective, and environmentally friendly process that might be employed as a viable alternative to conventional techniques of pollution removal. When it comes to improper textile waste disposal, it falls under one of the branches of bioremediation that is used to reduce contamination in the setting of improper textile waste disposal. The sorption isotherm of Cibacron Blue onto bean peel were analyzed using three models—pseudo-1st, pseudo-2nd and Elovich, and fitted using non-linear regression. The Elovich model was the poorest in fitting the curve based on visual observation and the best was pseudo-2nd order based on statistical analysis such as root-mean-square error (RMSE), adjusted coefficient of determination (adjR2), bias factor (BF), accuracy factor (AF), corrected AICc (Akaike Information Criterion), Bayesian Information Criterion (BIC) and Hannan–Quinn information criterion (HQC). Nonlinear regression analysis using the pseudo-2nd order model gave values of equilibrium sorption capacity qe of 6.164 mg/g (95% confidence interval from 5.918 to 6.410 ) and a value of the pseudo-2nd-order rate constant, k2 of 0.034 (95% confidence interval from 0.024 to 0.045). Further analysis is needed to provide proof for the chemisorption mechanism usually tied to this kinetic.

Kinetics Modeling on the Biosorption of Remazol Black B Dye by Aspergillus flavus

Azo dyes, such as Remazol Black B, are different from conventional dyes in that they establish covalent bonds with textile fibers like cotton. They are widely utilized in the textile industry because of their favorable properties of bright color, water resistance, simple application procedures, and low energy consumption. Their discharge into receiving streams has major environmental consequences, such as reducing photosynthesis in aquatic life due to lower light penetration. The biosorption isotherm data of Remazol Black B dye biosorption by Aspergillus flavus were investigated using two models—pseudo-1st order and pseudo-2nd order—and fitted using non-linear regression. The pseudo-1st order model was found to be the best by statistical analysis using root-mean-square error (RMSE), adjusted coefficient of determination (adjR2), bias factor (BF), accuracy factor (AF), corrected AICc (Akaike Information Criterion), Bayesian Information Criterion (BIC), and Hannan–Quinn information criterion (HQC). At 250 mg/L, kinetic analysis using the pseudo-1st order model yielded an equilibrium sorption capacity qe of 4.61 mg/g (95 % confidence interval from 4.54 to 4.68) and a pseudo-1st-order rate constant, k1 of 0.15 (95% C.I. from 0.128 to 0.164).

Kinetic Analysis of the Adsorption of Malachite Green onto Graphene Oxide Sheets Integrated with Gold Nanoparticles

Malachite green is extensively used in the textile dye industry and in agriculture as fish pests’ pesticide. Biosorption is a type of sorption technique that uses a biological sorbent. As of now, biosorption is viewed as a simple and cost-effective process that might be used as an alternative to traditional pollution treatment methods. Bioremediation is one of the branches of bioremediation that is used to minimise pollution in the context of incorrect textile waste disposal. The sorption isotherm of Malachite Green onto graphene oxide were analyzed using three models—pseudo-1st, pseudo-2nd and Elovich, and fitted using non-linear regression. The Elovich model was the poorest in fitting the curve based on visual observation and the best was pseudo-2nd order based on statistical analysis such as root-mean-square error (RMSE), adjusted coefficient of determination (adjR2), bias factor (BF), accuracy factor (AF), corrected AICc (Akaike Information Criterion), Bayesian Information Criterion (BIC) and Hannan–Quinn information criterion (HQC). Nonlinear regression analysis using the pseudo-2nd order model gave values of equilibrium sorption capacity qe of 6.164 mg/g (95% confidence interval from 5.918 to 6.410) and a value of the pseudo-2nd-order rate constant, k2 of 0.034 (95% confidence interval from 0.024 to 0.045). Further analysis is needed to provide proof for the chemisorption mechanism usually tied to this kinetic.