Search

Dyes provide a notable environmental issue as a result of their intrinsic poisonous and carcinogenic characteristics. An estimated 60,000 metric tons of dyes has been discharged into the environment, leading to a substantial increase in water pollution. The mitigation of these dyes is a substantial and intricate challenge. The primary objective of this research is to conduct a comprehensive analysis of the adsorption of cationic dyes containing positively charged groups such as sulphonates, amines, and triphenylmethanes. The adsorption study was carried out using four different low-cost adsorbents derived from biowaste, specifically Groundnut Shell (GS), Mosambi Peel (MP), Mango Bark (MBARK), and Mango Leaves (ML). The adsorbent materials were characterized using FTIR, UV–Vis spectroscopy, scanning electron microscopy (SEM), point-of-zero charge (PZC), and BET techniques. The adsorption capacity was found to be between 1.5 and 2.2 mg/gm for Groundnut Shell, Mosambi Peel, Mango Bark, and Mango Leaves for individual dye removal (Crystal violet, Methylene blue, Rhodamine B, and Malachite green). It was observed that adsorbent derived from mango bark showed excellent adsorption (%) in a mono-component dye system and, thus, was explored for the simultaneous removal of a mixture of the same dyes. MBARK exhibited an excellent overall dye removal efficiency of 94.44% (Qe = 2.7 mg/g) for the dye mixture in 60 min. From a detailed kinetic investigation, it was concluded that the adsorption followed the pseudo-second-order model (R2= 0.99963 to 1 for different dyes and adsorbents) hinting at chemisorption. The effect of the pH of the analyte solution and the dosage of adsorbent was also studied for simultaneous removal. The isothermal studies demonstrated that the Langmuir adsorption model (R2 = 0.99416) was the best-fitted model, suggesting monolayer adsorption. The adsorption process was predicted to be governed by ion exchange, electrostatic interaction, hydrogen bonding, pi–pi interaction, etc., based on charge, functional groups, and pH of dyes and adsorbent. Thus, this study highlights the application of low-cost biowaste as a potential adsorbent for the mitigation of toxic industrial dyes present in wastewater. [ABSTRACT FROM AUTHOR]

The present investigation deals with the importance of interaction and position of the nitro group in the adsorptive removal of 2-nitrophenol (2-NP), 4-nitrophenol (4-NP) and phenol by demineralized kraft lignin activated carbon (DKLAAC). The adsorption of phenol and NPs on DKLAAC was found to follow the order 2-NP > 4-NP > phenol. In this study, both solubility and donor–acceptor complex mechanism played an important role besides the porosity and surface area of the materials. Accordingly, the NP possessing the least solubility would noticeably exhibit a higher affinity to be adsorbed at the solid–liquid interface. Thus the highly hydrophobic 2-NP was adsorbed to a greater extent followed by 4-NP and phenol. Moreover, the adsorption capacity as affected by contact time, initial phenol concentration, pH, and temperature was also investigated. The experimental adsorption capacity by DKLAAC was 2.09, 2.34, and 2.20 mmol·g−1 for phenol, 2-NP, and 4-NP at 25 °C, respectively, with the maximum amount being adsorbed within 40 min. The experimental data obtained for the removal of phenol and NPs were adequately fitted by the Langmuir adsorption isotherm and pseudo-second order kinetic models. Additionally, the temperature study revealed the adsorption process to be endothermic and spontaneous with high affinity between DKLAAC and phenols. [ABSTRACT FROM AUTHOR]

The present work aims to provide insight into the role of the functional group in the adsorption of azo dyes namely, ethyl orange (EO), methyl orange (MO), and metanil yellow (MY), on the activated carbon (surface area 569 m2·g−1) prepared from Phyllanthus emblica fruit stone by low-pressure hydrothermal treatment (AC-HTPEFS). More specifically, this study would facilitate a better understanding of the involvement of different amino substituents (-CH3, -C2H5, phenyl group) on the adsorption of azo dye molecules. The experimental adsorption isotherms of the azo dyes quantified with different adsorbents and temperatures (25–45 °C) were utilized to know the effect of functional groups on dye adsorption. Additionally, the equilibrium data were analyzed by applying isotherm models (Freundlich, Langmuir, and Temkin) in order to elucidate the best-fit isotherm model and adsorption capacity, with the Langmuir model fitting the isotherms best as shown by the higher correlation coefficients obtained (0.984–0.994). The Langmuir monolayer adsorption capacities of EO, MO, and MY obtained at 25 °C were found to be 0.202, 0.187, and 0.158 mmol·g−1, respectively, which was attributed to the hydrophobicity and geometry of dye molecules. Moreover, adsorption kinetics conformed well with the pseudo-second-order model. The negative ΔG°, positive ΔH,° and positive ΔS° indicated the adsorption process to be favorable, endothermic, and increased randomness at the solid–liquid interface. Our findings indicate that the porous activated carbon from hydrothermally treated Phyllanthus emblica fruit stone exhibited a promising potential for the removal of azo dyes with rapid kinetics and high adsorption capacity. The present study could thus pave a way for future utilization of activated carbons produced via hydrothermal treatment techniques for wastewater applications. [ABSTRACT FROM AUTHOR]

Novel γ-alumina nanoparticles and MWCNTs were synthesized for the rapid removal of the noxious nickel (II) from the solvent phase. Hence this study investigated the ability of nano-sized particle in Ni (II) adsorption. The influential parameters including contact time (min), adsorbent dosage (g/L), pH and the initial concentration of Ni (II) were investigated and optimized using the batch adsorption study. The adsorption equilibrium and kinetic data were well fitted and found to be in good agreement with Langmuir and pseudo-second order kinetic model respectively and the maximum Ni (II) percentage removal using MWCNTs and novel γ-alumina nanoparticle was 87.65% and 99.41%, respectively under optimum conditions. The maximum removal of Ni (II) was observed at pH = 10. Upon experimentation, it was observed on increasing the adsorbent dosage and initial concentration the amount of Ni (II) removal efficiency also increased. Finally, it can be concluded that the synthesized nanoparticles can be applied as the best adsorbent to remove the Ni (II) from aqueous solution. [ABSTRACT FROM AUTHOR]

Iron nanoparticles loaded on ash (nFe-A) synthesized from a natural source i.e. Rosa canina L. leaves (as agricultural waste), were used as adsorbent for the rapid removal of the toxic Malachite Green (MG) dye from the liquid phase. Several effective parameters such as solution pH, initial dye ion concentration, contact time, adsorbent dosage and temperature were well studied and optimized using a batch adsorption method. The obtained experimental data revealed that a maximum amount of MG ions was removed within 5 min of contact time, hence it is the optimized contact time and after the 30 min of commencement of every experiment the equilibrium is attained, additionally the optimized value for initial dye ion concentration and solution pH was found to be 50 mg/l and 8 respectively. The adsorption equilibrium and kinetic data were well fitted and found to be in good agreement with the Langmuir isotherm model and pseudo-second-order-model. Moreover the negative value of ΔG° reveals the spontaneous nature of the adsorption process and the positive values of ΔH° and ΔS° indicate that the adsorption process is endothermic and entropy driven. [ABSTRACT FROM AUTHOR]

• Europium radionuclides were selected as model pollutant. • Real samples such as natural and seawater is used. • Novel nanocomposite material namely MPC is applied as adsorbent. • MPC possessed high specific surface area ∼ 2360 m2/g. Liquid radioactive waste (LRW) presents the most significant environmental hazard due to its high aggregate activity and rapid distribution in the environment. The paper presents the structure and adsorption characteristics features of a new nanocomposite material namely mesoporous carbon (MPC). Characterization studies depicts that the material obtained consisted of bundles of carbon nanotubes coated with a uniform layer of porous carbon shell. The study on the MPC porous structure disclosed that the resulting material possess a combination of micro and mesopores with a predominant size of 1–6 nm and a specific surface area of 2360 m2 g−1. Adsorption characteristics of the MPC were studied using the sorption of 152Eu radionuclide from natural and seawater. Activated charcoal, coconut charcoal, and a gel-type strong-acidic sulfonic cation exchanger were used as reference materials. The synthesized MPC was found to have the distribution coefficients (K d) of 152Eu over 3 × 106 cm3 g−1, which was 1–3 orders of magnitude higher than for the reference sorbents. The kinetics study of the 152Eu sorption on the MPC showed that the sorption equilibrium was attained in 5 min, three times less than the activated charcoal. High adsorption of MPC is associated with the colloidal of europium species on the developed surface of the carbon sorbent. Results conclude that the synthesized mesoporous carbon material makes a promising adsorbent for removing europium and other radionuclides, namely, cerium, lanthanum, zirconium, plutonium, and americium, from neutral solutions, where those radionuclides exist in either colloidal or pseudo colloidal form. [ABSTRACT FROM AUTHOR]

• Biogases (biomethane) and natural gas (methane) have huge potential for the development of the biogas industry. • Efficiency criteria for the adsorption storage systems for biomethane and natural gas (methane) have been established. • Potential of Porous carbon material from Biomass as Energy Storage material was explored. • Comparison based on sorption capacity of porous carbon-based materials for biomethane and natural gas (methane) have been summarized. Due to environmental performance, biogas (biomethane) and natural gas (methane) are at the center of attention among renewable fuels due to environmental performance. Gas fuels have significant environmental advantages over traditional petroleum-based fuels or fossil fuels. Adsorption technology for methane adsorption, storage, and transportation (biomethane and natural gas) can link gas supplies to consumers. The review considers the advantages of biomethane and natural gas as energy sources. The efficiency criteria for methane carbon-based storage systems have been analyzed and discussed. Porous carbon-based adsorption materials have been found to be very useful in methane adsorption, storage, and transportation. The outstanding characteristics of carbon materials such as high surface area and large pore volume, tunability, high abundance of precursors, thermal stability, and environmental friendliness are important features for their extensive usability. The findings on the sorption capacity of porous carbon-based materials for biomethane and natural gas have been discussed in detail and summarized. Based on the findings, it was found that the ANG technology has great potential for using natural gas and biomethane in the transport sector, provided that an appropriate adsorbent with suitable properties is applied. [ABSTRACT FROM AUTHOR]

The organic–inorganic hybrid nanocomposite of polyaniline/zirconium oxide was synthesized through the chemical method, using the ammonium persulfate as an oxidant. The developed adsorbent was characterized using various analytical techniques such as scanning electron microscopy, X-ray diffraction and Fourier transform infrared spectroscopy. The developed nanocomposites i.e. polyaniline modified with ZrO 2 and polyaniline were used as effective adsorbents for the rapid removal of methylene blue from the solvent phase. The effects of different system variables such as initial dye concentration, temperature and contact time were well studied and investigated. From the optimized parameter results obtained it was found that as contact time increases, the dye removal efficiency also increases. Additionally as the temperature increased the amount of adsorption also increased. The results indicated that the polyaniline modified with ZrO 2 and polyaniline nanocomposite have considerable potential for the removal of methylene blue from aqueous solution. The adsorption capacities (qmax) of polyaniline modified with ZrO 2 (PANI/ZrO 2 ) and polyaniline (PANI) for methylene blue in terms of monolayer adsorption were 77.51 and 192.30 mg/g, respectively. [ABSTRACT FROM AUTHOR]

Efficient adsorbent graphene oxide (GO) and its derivative, i.e., thiol-functionalized graphene oxide (GO-SH), was used for the removal of noxious Pb(II) ion from the aqueous phase. Different amounts, i.e., 60, 80, and 100 mg of cysteamine, were used as functionalizing agent to functionalize the GO with thiol group; hence, three different nanocomposites, i.e., GO-SH1, GO-SH2, and GO-SH3were prepared from the different amount of the cysteamine. The developed nanocomposites were characterized using various analytical techniques such as Fourier transform infrared spectroscopy, scanning electron microscopy, and X-ray diffraction analysis. The whole removal and adsorption process was well illustrated and investigated. The impact of influential factors including initial concentration, pH, contact time, temperature, and concentrations cysteamine on the adsorption properties of Pb(II) from aqueous solution was well elucidated and optimized. The obtained equilibrium results were inserted in various adsorption isotherm models such as Langmuir (liner types I, II, III, and IV), Freundlich, Temkin, Helsey, and Dubinin-Radushkevich isotherms, it was found that the Langmuir (type I) model demonstrated was well fitted and in good agreement with the maximum adsorption of Pb(II) ion from aqueous solution. Thermodynamic functions, such as ∆G°, ∆H°, and ∆S° were calculated and it reveals that the adsorption of Pb(II) ion on all the surfaces was spontaneous and endothermic in nature. [ABSTRACT FROM PUBLISHER]

In this work, tin sulfide nanoparticles loaded on activated carbon (SnS-NP-AC) was synthesized and characterized using various analytical techniques, such as SEM, BET, XRD, and UV–Vis spectroscopy. The impact of influential parameters such as the contact time, adsorbent dosage, pH, and initial dye concentration was investigated and optimization was carried out using random forest model. The optimized values of influential parameters i.e. pH, contact time, adsorbent dosage, and initial dye concentration were found to be 1, 4 min, 0.03 g, and 15 mg L−1, respectively. At these optimized values CR achieve highest removal percentage (99%) and maximum adsorption capacity (384.6 mg g−1). The experimental equilibrium data were fitted to different adsorption isotherm models i.e. Langmuir, Freundlich, Tempkin, and Dubinin–Radushkevich, among them the Langmuir model is found to be the best fitted and well suited model for evaluating and analyzing the actual behavior of adsorption process. The Kinetic experimental data were well fitted and they are in good agreement with pseudo-second-order and intraparticle diffusion model. [ABSTRACT FROM PUBLISHER]

Graphene quantum dots have been synthesized using the microwave-assisted hydrothermal route. The surface textural and morphological structure of synthesized adsorbent i.e. graphene quantum dots was analyzed using various analytical techniques such as X-ray diffraction, Transmission electron Microscopy, Atomic Force Microscopy and N 2 adsorption-desorption instrumental techniques. The application of graphene quantum dots as an adsorbent for the removal of noxious pesticide compound i.e. oxamyl from aqueous solutions was well investigated and elucidated. The impact of several effective parameters such as effect of agitation speed, pH, adsorbent dose, contact time, temperature and initial concentration on sorption efficiency was studied and optimized using batch adsorption experiments. The optimized pH for maximum oxamyl adsorption was found to be 8.0 and for the maximum adsorption rates the adsorbent dose of 0.6 g was found to be optimum to carry out the adsorption with in less than 25 min of contact time. From the results obtained, it is clear that for all contact times, an increase in oxamyl concentration resulted in increase in the percent oxamyl removal. The adsorption equilibrium and kinetic data were well fitted and found to be in good agreement with the Langmuir isotherm and pseudo-second-order kinetic model. [ABSTRACT FROM AUTHOR]

A novel adsorbent, copper oxide nanoparticle loaded on activated carbon (CuO-NP-AC) was synthesized by a simple, low cost and efficient procedure. Subsequently, this novel sorbent was characterized and identified using different techniques such as scanning electron microscopy (SEM), X-ray diffraction (XRD), and laser light scattering (LLS). The effects of some variables including pH, adsorbent dosage, initial dye concentration, contact time and temperature were examined and optimized. The adsorption kinetic data were modeled using the pseudo-first-order, pseudo-second order, intraparticle diffusion and Elovich models, respectively. The experimental results indicated that the pseudo-second-order kinetic equation can better describe the adsorption kinetics. Furthermore, Langmuir, Freundlich, Tempkin and Dubinin–Radushkevich models were applied for analyzing adsorption equilibrium data of acid blue 129 (AB 129) on the as-prepared adsorbent, which suggested that the Langmuir model provides a better correlation of the experimental data. Also, thermodynamic parameters such as ΔH, ΔS, E a , S*, and ΔG were calculated. It was seen that the proposed adsorbent has high tendency and adsorption capacity for AB 129 adsorption in a feasible, spontaneous and endothermic way. [ABSTRACT FROM AUTHOR]

This study used the gas-blowing method to develop a nanoporous hydrogel using poly (3-sulfopropyl acrylate-co-acrylic acid-co-acrylamide) grafted onto salep. The synthesis of the nanoporous hydrogel was optimized by various parameters for maximum swelling capacity. The nanoporous hydrogel was characterized using FT-IR, TGA, XRD, TEM, and SEM analyses. Images from SEM showed numerous pores and channels in the hydrogel with an average size of about 80 nm, forming a honeycomb-like shape. The change in surface charge was investigated by zeta potential and revealed that the surface charge of the hydrogel ranged from 20 mV at acidic conditions to −25 mV at basic conditions. The swelling behavior of optimum superabsorbent hydrogel was determined under different environmental conditions, such as different pH values, ionic strengths of the environment, and solvents. In addition, the swelling kinetics and the absorbance under loading of the hydrogel sample in different environments were investigated. Moreover, Methyl Orange (MO) dye was removed from aqueous solutions using the nanoporous hydrogel as an adsorbent. The adsorption behavior of the hydrogel was examined under various conditions, and the adsorption capacity of the hydrogel was found tobe 400 mg g−1. The maximum water uptake was obtained under the following conditions: Salep weight = 0.01 g, AA = 60 μL, MBA = 300 μL, APS = 60 μL, TEMED = 90 μL, AAm = 600 μL, and SPAK = 90 μL. Lastly, the adsorption kinetics was studied by employing pseudo-first-order, pseudo-second-order, and intra-particle diffusion models. [ABSTRACT FROM AUTHOR]

[Display omitted] • Pathways of CAP to enter the environment. • Effectiveness of novel adsorbents, AOPs, and biodegradation. • Isotherms, thermodynamic and molecular simulations. • Effect of water matrix on the performance of the adsorbents. • Clean regeneration technique for the CAP-exhausted adsorbents. Despite the carcinogenic and other adverse health effects ofchloramphenicol (CAP), it is frequently detected in different water sources (e.g., groundwater, surface water, wastewater effluents, etc.) due to ongoing, illegal, and abusive application of CAP in veterinary medicine. Although extensive research has been carried out to develop effective treatment technologies to remove the persistent CAP from aqueous mediums, yet there is no critical review of these studies to the best of our reach This review will be the first in the literature to comprehensively summarize the state-of-the-art treatment techniques for CAP removal from water. We report the removal of CAP by adsorption, biodegradation, nanoscale zerovalent iron technology (nZVI), and advanced oxidation processes (AOPs). The result shows that carbon-based adsorbents have more q max equal 892.86 mg/g for Porous carbon material from Enteromorpha prolifera. The Langmuir- Freundlich isotherm and pseudo-second order kinetics model were reported to best describe the isotherm and kinetic model respectively. Removing the CAP via biodegradation would achieve the advantages of low operating costs, and environmental friendliness. The process of AOPs among the various treatment options can be a promising method for CAP degradation in water. This review comprehensively summarizes the state-of-the-art treatment techniques for CAP removal from water. Particularly, serving as an inclusive reference for future researchers to easily define the research gabs in the literature and plan for their future work in developing novel treatment methods to decontaminate CA-contaminated waters. [ABSTRACT FROM AUTHOR]

[Display omitted] • The removal of Hg from environmental water by advanced oxidation processes. • The removal of Hg from environmental water by adsorption. • Thermodynamic molecular modelling and simulation of Hg adsorption. • Hg adsorption mechanism, kinetics and column adsorption studies. • Regeneration and reusability studies. The review discusses the removal of mercury (Hg) from wastewater by advanced oxidation processes (AOPs) and adsorption. The Hg adsorption in batch and column method was described, and the mechanism was explained, followed by the equilibrium and kinetic modelling. Furthermore, thermodynamic molecular modelling and simulation of Hg adsorption were discussed. The results showed that the removal of Hg from the aqueous solution by AOPs was successfully applied. Some of the future perspectives include enhancing the efficiency of the AOPs for the removal of Hg. The efficiency of available technologies for the removal of heavy metals in general and Hg in particular, depend on three criteria, namely efficacy, cost, suitability, and conditions of application. Langmuir and Freundlich isotherm models are best-fit and also pseudo second order kinetic model. [ABSTRACT FROM AUTHOR]

An extremely small size novel adsorbent, nickel hydroxide nanoplate loaded on activated carbon (Ni(OH)2-NP-AC) was synthesized using a simple, low cost and highly efficient method. The developed adsorbent was used for the removal of hazardous MG dye from the aqueous solution. To evaluate the importance of Ni(OH)2 nanoplates on the adsorption and removal process, the contact time of virgin AC and Ni(OH)2-NP-AC were compared (under the same conditions) that the results showed Ni(OH)2 nanoplate had a crucial role in the removal or adsorption process. The surface unique textural and morphological properties such as high surface area (>960 m2 g-1) and low pore size (<3.5 nm) made it possible for efficient and rapid removal of MG. Subsequently, the impact of various influential variables such as pH, adsorbent dosage, initial dye concentration, contact time and temperature were examined and optimized. The adsorption kinetic and equilibrium data of MG were found well fitted and found to be in good agreement with pseudo-second-order and Langmuir models, respectively. Finally, antibacterial activity of the synthesized nanoplates was evaluated by testing against some Gram-negative and Gram-positive bacteria. The results of this antibacterial testing indicated that the synthesized nanoplates showed effective bactericidal activity. [ABSTRACT FROM AUTHOR]

Removal of bromothymol blue (BTB) and methylene blue (MB) from wastewater using polyvinyl alcohol (PVA) has been elucidated in the present work.PVA exhibited high adsorption capacity and more active sites for the highly efficient removal of these toxic dyes. The impact of several variables such as concentration, contact time, pH and temperature were studied. The optimum pH and contact time for the high efficient removal were found to be 6 and 10 min, respectively. The adsorption isotherms were well interpreted by Freundlich and Langmuir models. The maximum adsorption capacities obtained from Langmuir model were 276.2 and 123.3 mg g − 1 for BTB and MB, respectively. In addition, the removal efficiencies for both adsorbates respectively, were found to be 98.65 and 61.32%. Several adsorption kinetic models were used to fit the experimental data, such as simple-first-order, the pseudo-first-order, pseudo-second-order and intraparticle diffusion models. The adsorption process concurrently adapted to the pseudo-second-order kinetics and it was found to be the best fitting model with the obtained experimental data. [ABSTRACT FROM AUTHOR]

Rapid adsorption of Triamterene using multi-walled carbon nanotube (MWCNT) and single-walled carbon nanotube (SWCNT) was well investigated and elucidated. The impact of influential variables such as temperature, amount of adsorbent, initial drug concentration, contact time was modeled using multiple linear regression (MLR) and artificial neural network (ANN) and the influential variables were optimized using genetic algorithm (GA). The adsorption equilibrium and kinetic data was well fitted and found to be in good agreement with the Langmuir monolayer isotherm model and pseudo second order kinetics mechanism. The maximum adsorption capacity of SWCNT and MWCNTs for the removal of Triamterene was found to be 25.77 mg g − 1 and 33.14 mg g − 1 respectively. The negative value of adsorption enthalpy (ΔH°) reveals towards the exothermic nature of the adsorption process. Based on the results comparison of the proposed models, results revealed that the applicability of the ANN model is more appropriate in comparison to the MLR model for predicting the adsorption efficiency of the process. The coefficient of determination (R 2 ) of 0.980 and mean squared error (MSE) of 0.002 for adsorption on SWCNT 0.986 and 5.4e-04 on MWCNT were obtained, respectively using the optimal ANN model. [ABSTRACT FROM AUTHOR]

In the present study, defluoridation study of liquid phase with the help of multi-walled carbon nanotubes (MWCNTs) and single-walled carbon nanotubes (SWCNTs) were well investigated and elucidated. The impact of different experimental conditions such as solution pH, initial fluoride concentration, adsorbent dose, and contact time was well studied and optimized for the maximum fluoride removal from water. The experimental data were fitted by the Freundlich, Langmuir and Dubinin–Radushkevich (D–R) isotherm models and the related equilibrium constants were calculated. The results of the isotherm studies showed that fluoride removal by both adsorbents followed the Freundlich isotherm model. Kinetic studies were conducted and the results demonstrated that the experimental data were fitted well with the pseudo-second order kinetic model. Furthermore, two multiple regression-based equations were also derived to model the removal of fluoride from aqueous solutions by the carbon nanotubes. This study demonstrated that the polynomial equations satisfactorily described the behavior of the present defluoridation process for both MWCNTs ( R 2 = 0.913) and SWCNTs ( R 2 = 0.941). [ABSTRACT FROM AUTHOR]

Multi-walled carbon nanotube functionalized by Cysteamine composite (MWCNT-COOH-Cysteamine) was synthesized using a facile, two-step modification route. At first purification of MWCNT was carried out in H 2 SO 4 and HNO 3 , the solution earned was treated ultrasonically in order to attain the equilibrium temperature for functionalizing multi walled carbon nanotubes with the carboxylate (MWCNT-COOH). Second step involves the treatment of carboxylate functionalized MWCNTs with the Cysteamine hydrochloride and NHS and DMF and EDC, the mixture was refluxed, which was later on characterized using various analytical techniques such as XRD, FT-IR, FE-SEM and TGA. The adsorption characteristics of MWCNT-COOH-Cysteamine were compared with MWCNT-COOH using Amido black 10B (AB10B) as an adsorbate in the present work. The effects of several influential parameters such as contact time, pH, and initial concentration on the adsorption were well investigated and optimized. The adsorption kinetics data for both MWCNT-COOH-Cysteamine and MWCNT-COOH were found to follow an intra-particle diffusion. [ABSTRACT FROM AUTHOR]

Tetraethylenepentamine-functionalized Rosa canina -L fruits activated carbon (TEPFRCA) was synthesized by microwave-assisted method for the fast adsorption and rapid removal of Malachite green (MG) from the solvent phase. The morphological and anatomical characterization of developed adsorbent was carried out using various analytical techniques such as FT-IR and FE-SEM. The impact of various influential parameters such as contact time (1–60 min), initial metal ion concentration (25–65 mg/L), temperature (298–333 K), adsorbent dose (0.001–0.025 g) and initial pH (1–8) of the solution was carried out using a batch adsorption method. The adsorption kinetic and equilibrium data process follows pseudo-second-order reaction kinetics (R 2 > 0.99) and the maximum adsorption capacity for TEPFRCA was 333.3 mg/g at 298 K. The whole process of adsorption of MG dye on to the developed adsorbent i.e. TEPFRCA was found to be spontaneous and endothermic under standard conditions. [ABSTRACT FROM AUTHOR]

Activated carbons decked with cuprous iodide–cupric oxide nano-composite were used as an adsorbent for the removal of lethal malachite green from the aqueous solution. The prepared adsorbent was characterized by means of various analytical techniques such as FE-SEM and XRD. To perk up the effectiveness of adsorption process, the effect of various influential parameters such as pH, adsorbent dosage, initial dye concentration, contact time and temperature were well elucidated and optimized using the batch experimental set-up. The optimum dosage, pH and contact time for CuI–CuO–AC were found to be 0.5 g/L, 7 and 20 min at 20 and 30 mg L − 1 of MG, respectively. The adsorption equilibrium data was examined using various well-known isotherm models such as Langmuir, Freundlich, Dubinin and Radushkevish and Tempkin, and it was observed that the experimental equilibrium data was well fitted and found to be in good agreement with the Langmuir model. Also, the thermodynamic parameters such as Δ H , Δ S , E a , S *, and Δ G were calculated and investigated, and on the basis of the obtained results we can conclude that the removal and adsorption process of MG was spontaneous and endothermic in nature. [ABSTRACT FROM AUTHOR]

This paper explores the possibility of employing Oxidized Multiwalled Carbon Nanotubes (MWCNT-COOH) for the removal of toxic Linear Alkyl benzene Sulfonate (LAS). LAS is among the most toxic industrial and house hold waste surfactants. This study discusses the feasibility of removing LAS from aqueous solutions using MWCNT-COOH. The effects of operational parameters such as solution pH, LAS concentration and contact time on the removal of LAS were studied. The four linear forms of Langmuir, Freundlich, Dubinin Radushkevich (D-R) and Temkin models were applied to determine the best fit of equilibrium expressions. Our results showed that the experimental adsorption isotherm complies with Freundlich model. The maximum adsorption capacity was determined to be 62.5 mg/g with an initial LAS concentration of 4 mg/L at pH 3 in 45 min. Fitting of the experimental results to kinetic models showed the relevance of the pseudo second-order (R 2 > 0.99) model for LAS. Our results confirmed that MWCNT-COOH would be promising adsorbents for LAS removal in aqueous solution. [ABSTRACT FROM AUTHOR]

Fe 3 O 4 nanoparticles were used as efficient adsorbent for the quick removal of ammonium ion from the solvent phase. The developed adsorbent was synthesized using a chemical co-precipitation method from its precursor mixtures i.e. FeCl 2 ·4H 2 O and FeCl 3 ·6H 2 O and which was further characterized using various analytical techniques such as Transmission electron microscopy and X-ray powder diffraction. The effect of various influential parameters such as contact time, pH, temperature and initial concentration was determined and optimized through a batch adsorption experiment. The optimized values of contact time, pH, temperature and initial concentration for adsorption were found to be 40 min, pH 10, T: 298 K and 140 mg/L of ammonium ions, respectively. The adsorption capacity of Fe 3 O 4 to adsorb ammonium ion in aqueous solution was well investigated and elucidated. The adsorption equilibrium data was found to be well fitted and in good agreement with the Langmuir isotherm model, which clearly depicts the strong interaction between the developed adsorbent and the ammonium ions; which directly leads to the rapid adsorptions of ammonium ion from the aqueous solution. [ABSTRACT FROM AUTHOR]

The present manuscript deals with the synthesis and application of zinc sulfide:copper nanoparticle loaded on activated carbon (ZnS:Cu-NP-AC) for the ultrasound-assisted removal of malachite green from water samples. ZnS:Cu nanoparticles were synthesized and characterized using FE-SEM and FTIR. The FE-SEM revealed the formation of nano-sized particles. Ultrasonic-assisted adsorption was optimized using response surface methodology (RSM) combined with UV–Vis spectrophotometry analysis. The important adsorption parameters viz. pH of MG solution, MG concentration, adsorbent and sonication time by Central Composite design (CCD) and Derringer’s desirability function. The optimal conditions were as followed: pH of 6.0, adsorbent of 0.02, sonication time of 3 min and MG concentration of 20 mg L −1 . The experimental checking in these optimal conditions confirmed good agreements RSM results. The results indicated that adsorption of MG on adsorbent was strongly dependent on adsorbent mass. The MG uptake by ZnS:Cu-NP-AC was quantitatively evaluated by using sorption isotherms such as Langmuir, Freundlich, Temkin and Dubinin–Radushkevich isotherm models, out of which Langmuir isotherm ( R 2 = 0.992) gave better correlation and maximum adsorption capacity was found to be 168.1 mg g −1 . [ABSTRACT FROM AUTHOR]

MWCNTs were used as an efficient adsorbent for rapid removal of hazardous Congo red dye (CR) from aqueous solutions; the whole adsorption process was well investigated and elucidated. The impact of several significant parameters such as contact time, pH, temperature and initial concentration were well studied and optimized. As a result of optimization the values of influential parameters such as contact time, pH, temperature, initial concentration and fixed adsorbent dose were found to be 60 min, 11, endothermic, 200 ppm and 0.05 g, respectively. The developed nano adsorbent shows an excellent potential (q e , 352.11 mg/g; 92% of CR has been removed within 60 min) for removal of CR from the solvent phase. The adsorption kinetics and isotherm data were found to be well fitted and in good agreement with the pseudo-second order and Langmuir isotherm models, respectively. The efficient and rapid removal of the noxious CR dye using MWCNTs in a very short period of time, and the obtained maximum adsorption capacity of the developed adsorbent in comparison to the previously developed adsorbent establishes the significance of the work done. [ABSTRACT FROM AUTHOR]

Adsorption capacity of Ni 2 + on graphene oxide (GO) and glycine functionalized graphene oxide (GO-G) surfaces was well investigated and elucidated. Amino group was used to functionalizing agent for the surface modification of GO to GO-G. The effect of numerous influential parameters such as contact time, temperature and initial concentration of Ni 2 + in the aqueous solution was well illustrated and optimized using batch adsorption study. The optimized values of adsorbent dose, initial concentration of Ni 2 + , contact time, and pH were found to be 20 mg, 15 mg/L, 50 min, and 6 respectively, ongoing through the impact of temperature it was seen that, when the temperature was increased from 283 to 308 K, the removal of Ni 2 + by GO surface decreased but the removal of Ni 2 + by functionalized GO-G surface decreased until 298 K and after that it was increased. Adsorption isotherm study for the adsorption process was carried out using four types of the Langmuir and Freundlich isotherm models. Results clearly depict that adsorption of Ni 2 + ions on to the GO adsorbent surface was well fitted and found to be in good agreement with the type (II) Langmuir isotherm model as the obtained regression constant value (R 2 ) is found to be 0.999 while the adsorption of Ni 2 + on GO-G surface was found to be in good agreement with the Freundlich isotherm model because the regression constant value (R 2 ) is found to be 0.999. [ABSTRACT FROM AUTHOR]

Application of activated carbon prepared from Pomegranate wood modified with 1-(2-fluorobenzoyl)-3-{3-[3-(2-fluorobenzoy)-thioureido]-phenyl}-thiourea for the rapid removal of toxic metal ion impurities was investigated. The impact of several parameters, like ion concentration, pH, contact time, adsorbent dosage, and temperature was elucidated and optimization was carried out using of bee algorithm superimposed with response surface methodology, the obtained optimum experimental conditions for the parameters i.e. ion concentration, pH, contact time, adsorbent dosage, and temperature are 28.6 mg L − 1 , 5.6, 70 min, 1.6 g, and 36.1 °C respectively. The experimental isotherm data reveals the suitability and applicability of the Langmuir isotherm model (R 2 = 0. 997) and kinetic data was found to be in good agreement with the pseudo second-order equation (R 2 = 0.9961) model. Thermodynamic parameter studies i.e. ∆G negative reveal the feasibility, and positive ∆H values confirm the endothermicity of the process. [ABSTRACT FROM AUTHOR]

Carboxylate group functionalized multi-walled carbon nanotubes (MWCNT–COOH) were synthesized by microwave-assisted method and characterized by Infrared spectroscopy; XRD methods and scanning electron microscope (SEM). These were used as adsorbent for the rapid removal of hazardous toxic dye Malachite green (MG) from aqueous phase. The impact of several effective parameters such as contact time, temperature, initial concentration, and agitation speed was investigated and the optimized values of influential parameters like pH, contact time, temperature, initial concentration, and agitation speed on experimentation were found to be 6, 50 min, 298 K, 15 mg/L and 150 rpm respectively. The experimental kinetic data were well fitted to the pseudo-first order reaction kinetics and results. Different adsorption isotherm models like Freundlich, Langmuir and Temkin are used to describe equilibrium adsorption in the adsorbent system and on experimentation the best agreement was achieved with the Langmuir model, for MG, the adsorption capacity of MWCNT–COOH surface was 49.45 mg/g at 298 K. [ABSTRACT FROM AUTHOR]

This work reports a comprehensive study of the adsorption characteristics of cadmium(II) on modified structures of carbon nanotubes (CNTs), carbon nanofibres (CNFs), activated carbon (AC), and fly ash (FA). The characterization was performed using field emission scanning electron microscopy (FE-SEM), thermogravimetric analysis (TGA) and Brunauer–Emmett–Teller (BET) surface analysis. Several experimental parameters; adsorbent dosage, pH, and agitation speed and contact time, were investigated for their effects on the adsorption of cadmium(II) from water. The optimum conditions of 2 h of contact time, pH 7, 50 mg adsorbent dosage and 150 rpm rotational speed were observed. Models of first-order, second-order and pseudo-second-order were fitted to the experimental data, and pseudo-second-order kinetics were observed to describe the adsorption of cadmium(II) on these adsorbents. The adsorption behaviours of cadmium(II) were evaluated using the Freundlich and Langmuir isotherm models. The maximum adsorption capacities of the modified adsorbents were observed to be 2.02 mg/g, 1.98 mg/g, 1.22 mg/g and 1.58 mg/g, for CNTs, AC, CNFs and FA, as obtained from Langmuir isotherm models. It was determined that surface modification of the CNTs, CNFs, and AC enhanced their adsorption efficiency. The results obtained are promising for the use of these modified materials with respect to water purification applications. [ABSTRACT FROM AUTHOR]

Highlights: [•] A novel carbon from microwave heating of rubber tire shows enhanced porosity. [•] Superior adsorption and kinetics demonstrated as a result of microwave heating. [•] Reveals its advanced adsorbent potential for wastewater treatment. [•] Demonstrates microwave heating advantages for carbon preparation. [•] Additional benefits like cost effectiveness and environmental friendliness. [ABSTRACT FROM AUTHOR]