Pseudo-second Order Kinetic Model Research Articles

Removal of Cr6+ ions and mordant violet 40 dye from liquid media using Pterocladia capillacea red algae derived activated carbon-iron oxides

In recent years, water pollution has become one of the most dangerous problems facing the world. Pollution of water with heavy metals and different dyes has caused many harmful effects on human health, living organisms and our environment. In this study, iron oxide nanomagnetic composite from Pterocladia Capillacea red algae-derived activated carbon (PCAC-IO) was synthesized by co-precipitation method using different iron salts and different base solutions. The synthesized nanocomposite was investigated with various characterization techniques such as FTIR, BET, SEM-EDX, TEM, XRD, and VSM. The obtained PCAC-IO adsorbent was used for Cr6+ ions and Mordant Violet 40 (MV40) dye removal. The adsorption mechanism of Cr6+ ions and MV40 dye on PCAC-IO was examined using several adsorption and kinetic isotherm models. Langmuir and Freundlich models were investigated using experimental data. Pseudo-first-order (PFO), Pseudo-second-order (PSO) and intraparticle diffusion models (IPDM) were applied to identify the adsorption mechanism. It has shown that the PSO kinetic model fits better with the experimental data obtained from PCAC-IO. This result can be interpreted as the adsorption of the adsorbate on the nanocomposite as chemical adsorption. The optimum conditions for maximum Cr6+ ions removal (96.88%) with PCAC-IO adsorbent occur at room temperature, 5 g L−1 adsorbent concentration, 100 mg L−1 initial pollutant concentration, pH 1 and at the end of 180 min, while maximum MV40 dye removal (99.76%), other conditions being the same, unlikely it occurred at pH 2.06 and after 45 min. The most suitable model for Cr6+ ions removal under the conditions of 1 L−1 g adsorbent concentration and 400 mg L−1 adsorbate concentration was Langmuir (Qmax = 151.52 mg g−1), while for MV40 removal it was Freundlich (Qmax = 303.03 mg g−1). We propose the use of activated carbon-supported iron oxide prepared from bio-waste material, especially from Pterocladia Capillacea red algae, as a promising adsorbent with high efficiency in the removal of Cr6+ ions and MV40 dye from aqueous media.

Novel MOF(Zr)-on-MOF(Ce) adsorbent for elimination of excess fluoride from aqueous solution

Herein, we used a one-pot method to fabricate a novel MOF-on-MOF adsorbent, namely MOF(Zr)-on-MOF(Ce). The adsorbent demonstrated a high maximum fluoride-ions capture capacity of 164.47 mg g−1. The morphology, elemental distribution, pore size distribution, and thermal stability were studied using SEM-EDS, XRD, BET, and TGA. The influence of the temperature, solution pH, fluoride concentration, and coexisting ions was explored using intermittent experiments. The results suggested that MOF(Zr)-on-MOF(Ce) had a fast capture rate for fluoride. MOF(Zr)-on-MOF(Ce) maintained an excellent fluoride removal performance over a wide pH range with an initial fluoride concentration of 20 mg L−1. The optimal effect was obtained at a pH of 4, but a high removal efficiency of 94% was maintained even at a pH of 9. Interference experiments showed that only the PO43– had an adverse inhibition influence. The field experiments demonstrated that MOF(Zr)-on-MOF(Ce) can keep the safety threshold levels of fluoride in drinking water. The Langmuir and pseudo-second order kinetic models were well fitted for the defluoridation process, demonstrating that the adsorption of fluoride ions on MOF(Zr)-on-MOF(Ce) was dominated by monolayer chemisorption. With the further characterization and kinetic thermodynamic studies indicates that the removal mechanism involves ion exchange, electrostatic interactions and complexation effect.

Sponge-like biodegradable polypyrrole-modified biopolymers for selective adsorption of basic red 46 and crystal violet dyes from single and binary component systems

Recently, several researchers have been trying to reduce the ecological effects of water pollution by considering the use of biodegradable materials that prevent the generation of secondary pollution in our environment and enable water reuse. Here, new biodegradable hydrogels based on alginate (Alg), gelatin (Gel) and polypyrrole (PPy) were successfully implemented to remove two known highly toxic cationic dyes from wastewater. The design process was performed in two steps: in-situ polymerization of polypyrrole within the Alg/Gel mixture, followed by hydrogel formation. Biocomposites showed promising efficacy for the removal of both basic red 46 (BR46) and crystal violet (CV) dyes from real and demineralized water samples. However, Alg-Gel-PPy hydrogel showed better selectivity for BR46 than for CV as compared to the pristine Alg-Gel hydrogel. Adsorption of both pollutants on biocomposite hydrogel beads followed the Langmuir isotherm and pseudo-second order kinetic models. Besides, the highest adsorption capacities (125 mg g−1 for BR46 and 88.5 mg g−1 for CV) were obtained for the Alg-Gel-PPy hydrogel, compared with those determined for PPy-free hydrogel (103.09 mg g−1 for BR46 and 86.96 mg g−1 for CV) and remained at a satisfactory level for five adsorption-desorption cycles. Finally, the obtained hydrogels showed excellent biodegradability by natural soil microorganisms, with 91 % decomposition.

Machine learning-based modeling of malachite green adsorption on hydrochar derived from hydrothermal fulvification of wheat straw

This study investigated the efficiency of hydrochar derived from hydrothermal fulvification of wheat straw in adsorbing malachite green (MG) dye. The characterizations of the hydrochar samples were determined using various analytical techniques like SEM, EDX, FTIR, X-ray spectroscopy, BET surface area analysis, ICP-OES for the determination of inorganic elements, elemental analysis through ultimate analysis, and HPLC for the content of sugars, organic acids, and aromatics. Adsorption experiments demonstrated that hydrochar exhibited superior removal efficiency compared to feedstock. The removal efficiency of 91 % was obtained when a hydrochar dosage of 2 g L−1 was used for 20 mg L−1 of dye concentration in a period of 90 min. The results showed that the study data followed the Freundlich isotherms as well as the pseudo-second order kinetic model. Moreover, the determined activation energy of 7.9 kJ mol−1 indicated that the MG adsorption was a physical and endothermic process that increased at elevated temperatures. The study also employed an artificial neural network (ANN), a machine learning approach that achieved remarkable R2 (0.98 and 0.99) for training and validation dataset, indicating high accuracy in simulating MG adsorption by hydrochar. The model's sensitivity analysis demonstrated that the adsorbent dosage exerted the most substantial influence on the adsorption process, with MG concentration, pH, and time following in decreasing order of impact.

Removal of Pb2+ from aqueous solution using an MgO nano-hybridized magnetic biochar from spent coffee grounds

An MgO nano-hybridized magnetic biochar (MMB) was successfully prepared from spent coffee grounds to remove Pb2+ from aqueous solution. It was the first time that carbon-based MgO composites were prepared by hydrothermal synthesis. At 20 °C, the maximum adsorption capacity of MMB was 321.9 mg/g (pH 5). The adsorption kinetics followed Pseudo second-order kinetic model. The adsorption process of MMB was confirmed by the Langmuir isothermal model, indicating the adsorption reaction was a single-layer chemisorption on MMB surface. XPS, FTIR and XRD analyses indicated the adsorption mechanism included surface complexation, ion exchange reaction and surface precipitation, with surface precipitation playing the largest role.

Modeling and optimization study on degradation of organic contaminants using nZVI activated persulfate based on response surface methodology and artificial neural network: a case study of benzene as the model pollutant

Due to the complicated transport and reactive behavior of organic contamination in groundwater, the development of mathematical models to aid field remediation planning and implementation attracts increasing attentions. In this study, the approach coupling response surface methodology (RSM), artificial neural networks (ANN), and kinetic models was implemented to model the degradation effects of nano-zero-valent iron (nZVI) activated persulfate (PS) systems on benzene, a common organic pollutant in groundwater. The proposed model was applied to optimize the process parameters in order to help predict the effects of multiple factors on benzene degradation rate. Meanwhile, the chemical oxidation kinetics was developed based on batch experiments under the optimized reaction conditions to predict the temporal degradation of benzene. The results indicated that benzene (0.25 mmol) would be theoretically completely oxidized in 1.45 mM PS with the PS/nZVI molar ratio of 4:1 at pH 3.9°C and 21.9 C. The RSM model predicted well the effects of the four factors on benzene degradation rate (R2 = 0.948), and the ANN with a hidden layer structure of [8-8] performed better compared to the RSM (R2 = 0.980). In addition, the involved benzene degradation systems fit well with the Type-2 and Type-3 pseudo-second order (PSO) kinetic models with R2 > 0.999. It suggested that the proposed statistical and kinetic-based modeling approach is promising support for predicting the chemical oxidation performance of organic contaminants in groundwater under the influence of multiple factors.

Robust functionalized cellulose-based porous composite for efficient capture and ultra-fast desorption of aqueous heavy metal pollution

The heavy metal pollution control industry requires convenient and cost-effective solutions to address complex aqueous environment. Adsorption method can be an effective strategy to realize these goals. Considering the importance of environmental and sustainable development strategies, there is an urgent need to develop efficient, green and non-toxic heavy metal adsorbents. In this work, a robust aminated cellulose-based porous adsorbent (PGPW) was developed from delignified wood and amino-rich polymer using a solvent-free, mild, simple and efficient preparation method. Such adsorbent exhibited excellent adsorption capacity (188.68 mg g−1) for Cu(II), and its adsorption behavior was consistent with pseudo-second order kinetic and Langmuir isotherm models. Notably, PGPW with superior compressibility could be squeezed to achieve rapid desorption and reach equilibrium within 5 min, while still retaining 87 % adsorption efficiency after 50 cycles. In addition, PGPW showed remarkable selectivity towards various coexisting ionic systems and demonstrated a considerable adsorption capacity in natural water applications. The adsorption mechanism of heavy metal ions on porous adsorption material was elucidated. This approach provides a simple, gentle and sustainable strategy for preparing functionalized wood-based composites with efficient adsorption and ultra-fast desorption of heavy metal ions.

Enhanced photocatalytic degradation of polycyclic aromatic hydrocarbon by graphitic carbonitride-nickel (g–C3N4–Ni) nanocomposite

The objective of the present study is to synthesize g-C3N4–Ni nanocomposites composed of graphitic carbon nitride and magnetic nickel nanoparticles for benzopyrene degradation, which is one of the most potent polycyclic aromatic hydrocarbons (PAH) molecules. The concocted g-C3N4–Ni nanocomposites contained confined nanospheres with a mean particle dimension of 22 nm. Batch adsorption studies revealed that a rise in adsorbent dosage elevates benzopyrene degradation percentage in both water and soil samples with respect to time. The increase in the benzopyrene concentration did not have much influence on the degradation efficiency, and hence, the minimal concentration of PAH molecule is essential for the effective adsorption by g-C3N4–Ni nanocomposites. The rise in pH tends to increase the degradation of Benzopyrene till 3 h of the incubation period, and beyond 3 h, the degradation percentage declines. With regard to the effect of light source, UV light has been shown to accelerate the degradation of benzopyrene by g-C3N4–Ni nanocomposites than sunlight. The adsorption kinetic and isotherm investigations have proven that the Pseudo-second order kinetic model and Freundlich isotherm model were appropriate for our study. Thus, the g-C3N4–Ni nanocomposites were found to be efficient as a photocatalyst for the adsorption of benzopyrene from environmental samples.

One-Step Fabrication of Recyclable Konjac Glucomannan-Based Magnetic Nanoparticles for Highly Efficient Cr(VI) Adsorption.

Recently, the natural polymer polysaccharide konjac glucomannan (KGM) has received attention as a promising adsorbent in water treatment due to its low toxicity, cost-effectiveness and biocompatibility. However, the high-level water absorbency of KGM makes it difficult to recover in water treatment. In this study, by combining KGM with magnetic nanoparticles, KGM-based magnetic nanoparticles (KGM-Fe3O4 NPs) with excellent adsorption properties and recyclability for heavy metals were prepared using an one-step precipitation method. The as-prepared KGM-Fe3O4 NPs have a spherical morphology of superparamagnetism with a small particle size (ca. 7.0 nm) and a large specific surface area (160.1 m2·g-1). Taking Cr(VI) as the target heavy metal ion, the above nanoparticles have a high adsorption capacity and fast adsorption rate for Cr(VI). The pseudo-second order kinetic model is more suitable to describe the adsorption process of Cr(VI) by KGM-Fe3O4 NPs, and the maximum adsorption capacity of Cr(VI) onto KGM-Fe3O4 NPs was calculated to be 41.67 mg·g-1 using the Langmuir isotherm model. In addition, KGM-Fe3O4 NPs with adsorbed heavy metal ions can be quickly recovered from a solution, regenerated, and reused in the next cycle. KGM-based Fe3O4 nanoparticles are promising adsorbents that show significant reusability for the removal of metal ions in water and wastewater treatment.

A Comparative Study of Adsorption of Methylene Blue Dye onto Untreated Platanus orientalis (chinar tree) Leaves Powder and its Biochar - Equilibrium, Kinetic and Thermodynamic Study

In the present investigation the adsorption behavior of methylene blue (MB) dye from aqueous solution onto untreated chinar leaves powder (CLP) and chinar leaves biochar (CLB) has been studied. To find out optimum conditions, adsorption process was carried out by varying different parameters such as contact time, adsorbent dose, concentration, temperature, salts, and pH. The equilibrium adsorption data were subjected to different popular isotherms (Langmuir, Freundlich, and Temkin) and kinetic models (pseudo-first order, pseudo-second order and intra-particle diffusion model). The thermodynamic study was also done on the adsorption process. The maximum monolayer adsorption capacities for MB dye onto given adsorbents are 1.53 mg/g (CLP) and 1.02 mg/g (CLB). Also the values of RL and n suggest favourable adsorption process of MB dye onto CLP and CLB adsorbents. The pseudo-second order kinetic model is best obeyed by both the mentioned adsorbents for MB dye adsorption with R2 value equal to 1. Thermodynamic study reveals that the adsorption process of MB dye is spontaneous, endothermic (CLB) and exothermic (CLP). At an equilibrium time of 20 min the uptake efficiency (> 99%) was recorded for both the low cost adsorbents (CLP and CLB) thus proved them fast and effective adsorbents for the removal of MB dye.

Sustainable removal of Pb (II) from aqueous medium by using chitosan functionalized Citrus limetta peels biomass

In this investigation, chitosan functionalized Citrus limetta peel biomass (ChCLP) was synthesized for adsorption of Pb (II). Results of energy dispersive X-ray (EDX) and X-ray photoelectron spectroscopic (XPS) confirmed the chitosan coating and adsorption of Pb (II). Functional groups like -NH2, C-H and -OH groups were present on the ChCLP surface. The surface of ChCLP was observed to be rough and porous. Langmuir isotherm was best fitted in the adsorption data. This indicated toward the monolayer adsorption of Pb (II) onto the homogeneous surface of the adsorbent. The suitability of pseudo-second order (PSO) kinetic model indicated chemisorption of Pb (II) onto ChCLP. Thermodynamic study revealed endothermic and spontaneous Pb (II) adsorption. Values of the diffusion coefficient and dimensionless numbers indicated that Pb (II) adsorption was mix diffusion and transfer controlled. It was found that both the experimental and predicted values for ChCLP was close to each other showing a high R 2 value in the range of 0.94 − 0.98. Results showed that ChCLP has high Pb (II) removal capacity (99.8%) at 100 mg/L and 10 g/L ChCLP dosage. ChCLP adsorbent showed a high regeneration capacity in five consecutive adsorption-desorption cycles.

Adsorptive Sequestration of Methylene Blue Dye from Aqueous Solution Using Novel Roystonea regia fruit Pericarp: Isotherm, Kinetics, and Thermodynamics

The batch adsorptive sequestration of methylene blue from an aqueous solution using unripe Roystonea regia fruit pericarp biomass was investigated in this study. The characteristic nature of the biosorbent was studied using various analytical instruments including Fourier Transform Infra-red spectrophotometer, Scanning Electron Microscope, Energy Dispersive X-ray, X-ray diffractometer, and the Brunauer-Emmett Teller. The adsorption study was perfomed at different experimental conditions including pH, contact time, initial dye concentration, temperature, agitation speed, and biosobent dose. From the results of this study, the optimum biosorption of MB was achieved at 120 min contact time, pH 10, room temperature (298 K), 150 rpm agitation speed and dosage of 100 mg/150 mL dye solution. With 132.30 mgg-1 maximum sorption capacity, the Langmuir isotherm best describes the biosorption equilibrium data. At all initial concentrations, the biosorption kinetics of methylene blue onto the biosorbent fitted best to the pseudo-second order kinetics model, with R2 values ≥ 0.999 and qcal being similar to the qexp. The kinetics study also showed the involvement of intra-particle diffusion in the rate-determining step; although not as the sole limiting step of the sorption process. The results of the thermodynamics study showed the high feasibility, spontaneity, and exothermic nature of the biosorption of methylene blue onto the biosorbent. This study concludes that Roystnea regia fruit pericarp would make an economically viable and renewable biosorbent for practical eco-friendly sequestration of MB dye from wastewaters.

Electrospun silk nanofibers for numerous adsorption-desorption cycles on Reactive Black 5 and reuse dye for textile coloration

Despite the fact that numerous effective adsorbents have been developed and the fact that adsorption is an appropriate technology for the removal of textile waste, cyclic adsorption-desorption and the reusability of collected waste dye have proven to be difficult to achieve thus far. Therefore, we report the fabrication of electrospun silk nanofibers (ESNFs) membranes for textile dye adsorption, desorption, and reusability. The surface morphology and chemical structure of ESNFs membranes were characterized using FE-SEM, FTIR and XPS techniques. We showed that ESNFs membranes can be efficient adsorbent for Reactive Black 5 (RB5) dye and 40 mg ESNFs have capacity to adsorb up to 98 % of RB5 (dye concentration 100 mg/L) in 5 mL volume of dye solution within 5 min at pH 5. Good physicochemical stability and physical attachment of RB5 on ESNFs membrane, enables a way for 20-time good cyclic adsorption-desorption. The experimental kinetic and isotherm data were well explained by pseudo-second order kinetic model and Langmuir adsorption isotherm model, respectively. Due to simple desorption achieved in alkaline DI water, we proposed a reusability of waste collected dye in textile coloration (cotton fabric coloration). As a result of these findings, we now know that ESNFS are an easy-to-use, cost-effective, resilient, and cyclic adsorbent that may serve as an alternative for various practical applications.

Adsorption of Cefixime from aqueous solutions by biochar prepared from pine leaves (<i>Pinus kesiya</i>)

Nowadays, water pollution due to antibiotics is a serious matter. This present research investigated to analyze the characteristics of biochar from pine leaves (Pinus kesiya) to remove the antibiotic Cefixime from aqueous solutions. The influence of some factors: pH (2-10); contact time (10-240 mins); initial concentration of Cefixime were carried out. The characterization of materials was determined by using FT-IR (Fourier Transform Infrared Spectrometer), BET (Brunauer - Emmett - Teller), and SEM (Scanning Electron Microscope). Biosorption data was suitable for Langmuir and Freundlich isotherm models. Through the linear equation of the Langmuir isotherm model, the maximum adsorption capacities of Cefixime (qmax) were 21,51 mg/g. The biosorption process obeyed the Pseudo second-order kinetic models. This research proves that biochar is a potential biosorbent for antibiotic Cefixime removal from an aqueous solution with high efficiency, low cost, and environmental friendliness.

Adsorption of Rhodamine b dye onto novel Biochar: Isotherm, Kinetic, thermodynamic study and antibiofilm activity

Wastewater pollution from organic dyes has been a serious and increasing environmental problem. The present work aims to synthesize and characterize biochar (BC) from shrimp shells for application as a biosorbent in the Rhodamine B (RhB) dye removal. Central Composite Rotational Design (CCRD 22) was used to determination of the ideal condition by adsorption process and BC was characterized by X-ray Diffraction (XDR), N2 porosimetry, zero charge point (pHZCP) and Scanning Electron Microscope (SEM). The toxicity was measured by 3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide (MTT) and 2,7 Dichlorofluorescein Diacetate (DCFH-DA) assay in 293 T, HaCat, and MDBK cell lines, and antibiofilm activity was carried out against P. aeruginosa, A. baumannii, S. epidermidis and E. coli strains. BC showed an irregular morphology (semi-cubic and plates), mesoporosity (Dp ∼ 12.3 nm), pore volume around 0.43 cm3 g−1, the surface area of the 101 m2/g and pHZCP = 7.34. The best experimental fit for the adsorption data was Freundlich isotherm (equilibrium) and pseudo second-order (PSO) (kinetic model) indication a chemisorption process with a maximum adsorption capacity of 350.55 mg g−1 with 72.34 % of RhB removal (pH = 9, T = 298 K and [BC] = 4.5 g/L). Moreover, a thermodynamic study confirmed a spontaneous process (ΔG < 0), endothermic (ΔH = 64.76 kJ mol−1) and with an increase in system randomness indicating structural alterations of the BC surface and the RhB adsorbed (ΔS > 0). Regarding the BC recycling, there was a reduction from 72.10 % (349.38 mg g−1) to 46.32 % (223.38 mg g−1) after V cycles. BC showed biocompatibility (except in the higher concentration) and important antibiofilm activity of 87.5 % (P. aeruginosa), 53.12 % (S. epidermidis), 68.93 % (A. baumannii) and 51.7 % (E. coli) to 125 µg mL−1. Therefore, it was possible to synthesize and characterize an alternative biosorbent from shrimp shell waste with high adsorption capacity, meeting the circular economy for wastewater treatment.

Comparative Study of Adsorption of Methylene Blue and Basic Red 9 Using Rice Husks of Different Origins

Methylene blue (MB) and basic red 9 (BR9) are cationic dyes that are commonly used in the dye industry and negatively affect humans and other living organisms. This study compares the performance of Indonesian rice husk (IRH) and Hungarian rice husk (HRH) as bio-adsorbents for removing MB and BR9 from aqueous solutions. Chemical content, zeta potential, and Fourier-transform infrared spectroscopy analyses were used to characterize the rice husks (RHs). Adsorption studies were performed through batch experiments involving several parameters, namely, pH, adsorbent dose, initial dye concentration, contact time, and temperature to observe the self-association (aggregation) of MB and BR9. Adsorption kinetic studies showed that maximum dye removal was achieved at a contact time of 120 min. MB and BR9 adsorption followed a pseudo-second order kinetic model, and the BET multilayer isotherm model provided a better fit to the experimental data of MB and BR9 adsorption. The IRH adsorption capacities were 15.0 mg/g for MB and 7.2 mg/g for BR9, whereas those of HRH were 24.4 mg/g for MB and 8.3 mg/g for BR9. Therefore, these RHs are potential bio-adsorbents for removing MB and BR9 from aqueous solutions.

A Glance at a Sustainable Solution Using Vertical Constructed Wetland Based on Dewatered Drinking-Water Waste Augmented Nanoparticle Composite Substrate for Wastewater Treatment

The current investigation introduces and demonstrates a credible, economically sound system to remove agrochemical runoff using a vertical flow constructed wetland (VFCW). DuPont 1179 carbamate insecticide was applied as a simulating greenhouse crop production controller, which resulted in runoff loaded with DuPont 1179. A novel composite of constructed wetland from an alum sludge conjugate magnetite nanoparticle substrate was applied and supported with gravel as a filtration/adsorption bed in a vertical flow constructed wetland (VFCW) system. X-ray diffraction spectroscopy (XRD), scanning electron microscopy (SEM) augmented with energy dispersive X-ray analysis (EDX), transmission electron microscopy (TEM) and Fourier transform infrared spectroscopy (FTIR) were employed to characterize the suggested composite substrate. The experimental data showed VFCW to be significant in eliminating DuPont 1179. The isotherm time was explored at 300 min, which corresponded to complete insecticide removal (100%). The operational parameters were located at the natural pH (6.9) of the solution and room temperature (25 °C). The VFCW column was also investigated at various substrate concentrations ranging from 100% to 40% of the composite material supported by a gravel medium, and the existence of composite at a 75% concentration showed the highest yield. The experimental data verified that the adsorption followed the pseudo second-order adsorption kinetic model. Furthermore, according to the isotherm model results, the scheme followed the Langmuir isotherm model. Thus, the presented study is a promising indicator of the possibility of using alum sludge conjugate nanoparticles for the elimination of agrochemicals from wastewater.

Removal of Mercury Ions from Aqueous Solutions Using Dithiooxamide-Glutaraldehyde Resin

ABSTRACT This work has been performed to synthesize a new dithiooxamide/glutaraldehyde resin (R-DTGA) polymer, and to determine the adsorption behavior as well as the adsorption kinetics of the reaction of the synthesized polymer towards the removal of mercury (II) ions from contaminated aqueous and industrial waste media. The synthesized resin polymer has been characterized by using the X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX), Fourier-Transform Infrared spectroscopy (FT-IR), the DTA, and the TGA measurements and techniques. The adsorption behavior of mercury ions and species was studied using the batch technique. The batch adsorption experiments were performed by using the synthesized polymer, and the effect of various parameters affecting the mercury (II) ions removal has been carefully investigated. The studied parameters are the solution pH, mercury ions concentration, and adsorption time. The obtained experimental results and data indicated the adsorption of mercury was maximum at the pH value (4.6). Also, it was found the adsorption of mercury ions onto the synthesized resin is best fitted by the Langmuir adsorption model, and the adsorption kinetics is best fitted by pseudo-second order kinetics model. The studied adsorbent polymer gave a superior maximum uptake (adsorption) capacity of 11 mmol/g. Based on the obtained results, the synthesized polymer provided extraordinary maximum capacity, selectivity, reusability, sensitivity, and fast adsorption kinetics to remove, extract, and recover mercury (II) ions from industrial, aqueous, and wastewater solutions.

Fabrication of core–shell Fe3O4@polypyrrole@sodium dodecyl benzene sulfonate composite for high-performance adsorption of methylene blue and malachite green in water

In this study, a novel composite material with a core–shell structure, Fe3O4@PPy@SDBS, was synthesized through a combination of hydrothermal, in situ polymerization, and surface modification methods. The primary objective was the removal of methylene blue (MB) and malachite green (MG) dyes from aqueous solutions. The influence of adsorbent type, time, initial adsorbent concentration, and temperature on the adsorption behavior of MB and MG was comprehensively investigated. The experimental results revealed that the adsorption kinetics of both MB and MG adhered to the pseudo-second order kinetic model, while the isotherm data were best described by the Langmuir isotherm model. Furthermore, the adsorption process exhibited characteristics of a spontaneous heat-driven reaction. The maximum adsorption capacities were determined as 124.07 mg/g for MB and 73.10 mg/g for MG, respectively. Remarkably, even after undergoing five desorption-adsorption cycles, the removal efficiencies for MB and MG remained above 80% and 90% respectively. These promising outcomes were attributed to the collaborative effects of electrostatic interactions, hydrogen bonding, and π-π interactions mediated by PPy and SDBS, in addition to the magnetic properties imparted by Fe3O4. Consequently, the Fe3O4@PPy@SDBS composite exhibited high potential as a proficient and reusable adsorbent. Beyond its efficient removal capabilities, the incorporation of magnetic properties and diverse adsorption mechanisms within these composites presents compelling opportunities for advancements in adsorption and separation processes.

Novel Magnetotactic Bacteria Strain for Enhanced Aluminium Ions Biosorption

Over the decades, the removal of heavy metals from aqueous solution using biosorbents such as algae, fungi, yeast, and bacteria has remained a challenging task. This paper explores the Al(III) biosorption efficiency of magnetotactic bacteria (MTB) via a new strain called SUM 123 of Alcaligenes sp. The influence of temperature, pH, initial Al(III) concentration, and adsorbent dosage on the biosorption efficiency of MTB is examined. The achieved optimum conditions for Al(III) ions biosorption in the aqueous solution is demonstrated to be 80 mg/L, 12 g/L biosorbent at 25 ºC with pH 5. In this situation, the isolated bacteria attained the maximal Al(III) loading capacity as much as 15.74 mg Al(III)/g (biomass) with 99.53% adsorption. Furthermore, better fitness of “the equilibrium data was provided by the Langmuir isotherm model compared to the Freundlich model. Again, the feasibility, spontaneous and endothermic nature of the biosorption process at 10-40ºC were validated by the evaluated thermodynamic parameters (ΔGº, ΔHº and ΔSº). A pseudo second-order kinetic model that fitted the kinetic data was also achieved with a correlation coefficient (R2) value of &gt; 0.993. FTIR spectra manifested the involvement of hydroxyl, amide, and amine groups in Al(III) biosorption process.” TGA displayed the existence of Al(III) adsorption on the cell wall. It is established that the SUM 123 biomass assisted biosorption is a prospective cost-effective method for Al(III) recovery from contaminated waters.