Adsorbent For Removal Research Articles

The use of artificial neural network for modelling adsorption of Congo red onto activated hazelnut shell.

Activated hazelnut shell (HSAC), an organic waste, was utilized for the adsorptive removal of Congo red (CR) dye from aqueous solutions, and a modelling study was conducted using artificial neural networks (ANNs). The structure and characteristic functional groups of the material were examined by the FTIR method. The BET surface area of the synthesized material, named HSAC, was 812 m2/g. Conducted in a batch system, the adsorption experiments resulted in a notable removal efficiency of 87% under optimal conditions. The kinetic data for hazelnut shell activated carbon (HSAC) removal of CR were most accurately represented by the pseudo-second-order kinetic model (R2 = 0.998). Furthermore, the equilibrium data demonstrated a strong agreement with the Freundlich model. The maximum adsorption capacity of HSAC for CR was determined to be 34.8 mg/g. The optimum adsorption parameters were determined to be pH 6, contact time of 60 min, 10 g/L of HSAC, and a concentration of 400 mg/L for CR. Considering the various experimental parameters influencing CR adsorption, an artificial neural network (ANN) model was constructed. The analysis of the ANN model revealed a correlation of 98%, indicating that the output parameter could be reliably predicted. Thus, it was concluded that ANN could be employed for the removal of CR from water using HSAC.

Adsorptive removal of cadmium from electroplating wastewater using hybrid composite of thiol-grafted seed gum of Tamarindus indica and Teff hay biocarbon

Abstract This study examined the methods for preparing biocarbon from Teff hay (TBC) and thiol-grafted seed gum of Tamarindus indica (TH@TI-TBC) with the purpose of removing cadmium (Cd) from polluted electroplating waste water. To improve biocarbon adsorption, seed gum and thiol were added in a two-step combination. At a pH of 5.5, the most effective Cd adsorption was seen with TH@TI-TBC (261.47 mg g−1). While comparing to the Freundlich and Temkin models, the Langmuir and pseudo-second-order kinetic models found to be the best fit to the obtained adsorption data. After being treated with electroplating wastewater having 30 mg−1 L of cadmium, TH@TI-TBC was able to remove up to 89 % of the Cd, proving its effectiveness in dealing with adsorptive removal of Cd. Experimental studies and computational analyses revealed that electrostatic interaction and surface complexation were the principal underlying processes for Cd removal by TH@TI-TBC. In addition, an innovative material that can transform the waste into a product for environmental remediation must be developed using the vast amounts of Teff hay that are generated as agro-residue. So, this work proved that TH@TI-TBC can be made from Teff hay biocarbon could be a potential candidate for removing Cd from industrial wastewater.

Efficient adsorption removal of carbamazepine from water by dual-activator modified hydrochar

The decontamination of trace micropollutants from water environments is a widely concerned issue, and developing green and efficient adsorbent serves as an effective solution. In this study, using dual-activator modification method, an efficient hydrochar adsorbent was prepared through a two-step sequential process combining H3PO4 hydrothermal treatment with K2CO3 pyrolysis activation for carbamazepine (CBZ) adsorption removal. The results indicated that H3PO4 facilitated the K2CO3 activation process. The prepared hydrochar exhibited excellent adsorption properties due to its high specific surface area (1265.08 m2·g−1) and aromatic porous mesh structure, with the maximum and dynamic adsorption capacity for CBZ of 376.11 and 296.98 mg·g−1, respectively. The adsorption mechanism primarily involved pore-filling effects, π-π electron-donor–acceptor (EDA) interactions and hydrophobic interactions. Additionally, the obtained hydrochar material showed high adsorption efficiency for various pollutants and performed well in actual water samples. This study may provide theoretical and technical support for the development and application of high-efficiency hydrochar-based adsorbents.

Arsenite oxidation and adsorptive arsenic removal from contaminated water: a review.

Arsenic poisoning of groundwater is one of the most critical environmental hazards on Earth. Therefore, the practical and proper treatment of arsenic in water requires more attention to ensure safe drinking water. The World Health Organization (WHO) sets guidelines for 10μg/L of arsenic in drinking water, and direct long-term exposure to arsenic in drinking water beyond this value causes severe health hazards to individuals. Numerous studies have confirmed the adverse effects of arsenic after long-term consumption of arsenic-contaminated water. Here, technologies for the remediation of arsenic from water are highlighted for the purpose of understanding the need for a single-point solution for the treatment of As(III)-contaminated water. As(III) species are neutral at neutral pH; the solution requires transformation technology for its complete removal. In this critical review, emphasis was placed on single-step technologies with multiple functions to remediate arsenic from water.

Adsorptive removal of arsenic from drinking water using KOH-modified sewage sludge-derived biochar

This paper reveals a green chemistry approach to remove arsenic (As+3) from water using potassium hydroxide (KOH) modified sewage sludge-derived biochar (SSDB-KOH). Characterisation of the morphology, particle size and composition of the SSDB-KOH pre- and post-adsorption confirmed porous and heterogenous surface favouring adsorption. At ambient temperature (20 °C), the SSDB-KOH dose of 20 g/l achieved 98 % arsenite removal at nearly neutral solution pH (8). This compared favourably with pristine SSDB, where the performance was limited to 41.6 % removal. The enhanced arsenite adsorption of SSDB-KOH was informed by several mechanisms, including ionic interactions, pore filling and metal-pi interactions. The experimental data fits closely with the Langmuir isotherm and pseudo-second-order kinetic models, revealing monolayer adsorption and the chemical interaction between adsorbents and the adsorbate. The spontaneous and endothermic nature of the process was confirmed by the negative value of ΔG and the positive value of ΔH, respectively. The performance of the biochar was evaluated for four-cycle regeneration. Finally, a cost analysis was performed to demonstrate the economic feasibility of using SSDB-KOH to remove arsenic from water.

Synthesis of Nanocomposite Based Polysaccharide and Performance Evaluation for the Removal of Various Drug from Pharmaceuticals Wastewater

AbstractThe present study performed synthesis and characterization nanocomposite based polysaccharide Chitosan/Agar and Chitosan/Agar/SiO2 nanoparticles as adsorbents for remove amoxicillin and naproxen as the pharmaceuticals from an aqueous solution. The structure and morphology of nanocomposite were investigated using X‐ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X‐ray spectroscopy (EDX), Fourier‐transform infrared spectroscopy (FTIR), Transmission electron microscopy (TEM), Field Emission Scanning Electron Microscopes (FE‐SEM) and Dynamic light scattering (DLS). The removal performance of the Chitosan/Agar and Chitosan/Agar/SiO2 nanoparticles nanocomposite as adsorbent for removing amoxicillin and naproxen as sample of pharmaceutical industry effluents in aqueous solutions was investigated under different influence factors, including contact time, initial concentration, pH conditions and temperature. The maximum adsorption removal for amoxicillin with Agar/Chitosan and Agar/Chitosan/SiO2 nanocomposite at initial concentrations of 20 mg/l was 97.85 % and 87.9 %, respectively. With increasing temperature from 10 to 30°C, the removal efficiency for naproxen for both adsorbents is 99 %. The prepared nanocomposites showed good performance in adsorbing naproxen and amoxicillin. The maximum adsorption efficiency of nanocomposite was 99 % and 91 % for naproxen and amoxicillin, respectively. The optimum condition for pharmaceuticals removal by the nanocomposite was initial concentration: 20 mg/l, adsorbent dose: 0.05 g, contact time: 10 min, and pH=6.

Highly Efficient Removal of 2,4,5-Trichlorophenoxyacetic Acid by Adsorption and Photocatalysis Using Nanomaterials with Surface Coating by the Cationic Surfactant.

Extensive removal of 2,4,5-trichlorophenoxyacetic acid (2,4,5-T) using titania (TiO2) nanoparticles by adsorption and photocatalysis with a surface coating by cetyltrimethylammonium bromide (CTAB) is reported. The CTAB-coated TiO2 nanoparticles (CCTN) were characterized by FT-IR, zeta-potential measurements, and UV-vis diffuse reflectance spectroscopy (UV-vis-DRS). 2,4,5-T removal increased significantly after surface modification with CTAB compared with bare TiO2 nanoparticles. Optimal parameters affecting 2,4,5-T removal were found to be pH 4, CCTN dosage 10 mg/mL, and adsorption time 180 min. The maximum adsorptive removal of 2,4,5-T using CCTN reached 96.2% while highest adsorption capacity was 13.4 mg/g. CCTN was also found to be an excellent photocatalyst that achieved degradation efficiency of 99.2% with an initial concentration of 25 mg/L. The removal mechanisms of 2,4,5-T using CCTN by both adsorption and photocatalysis are discussed in detail based on changes in functional group vibrations and surface charge. Our results indicate that CCTN is an excellent material for 2,4,5-T removal in water by both adsorption and photocatalysis.

Combined Effect of Adsorption and Photocatalytic Degradation Using Magnesium Oxide Nano-flowers for Tetracycline Removal

AbstractThe extensive use of antibiotics, including tetracycline (TC), has several negative impacts on ecosystems that need attention. In the present study, magnesium oxide nano-flowers (MgO NFs) were examined as an adsorbent and as a degradation photocatalyst for TC elimination. MgO NFs were characterized by XRD, UV-Vis, PL, SEM, TEM, and FTIR. Optimization of the removal process included varying the treatment time, initial pH, MgO NFs dosage, and testing with different initial TC concentrations. The highest removal efficiency (77.3%) was achieved for 50 mg/L TC using 0.6 g/L of MgO NFs at pH 9. Adsorption removal contributed to 26.0% of this removal, while 51.3% was attributed to photocatalytic removal. A one-way analysis of variance (ANOVA) revealed significant impacts of time, initial pH, MgO NFs dose, and initial TC concentrations on TC removal. Although adding different ions showed strong effects on TC adsorption on MgO NFs, those ions inhibited TC removal by about 5% after photocatalytic degradation. Adsorption data fitted well with the Langmuir isotherm and pseudo-second-order kinetic models, the adsorption process was monolayer on a homogenous surface based on chemical interactions. Based on the Langmuir-Hinshelwood model, t1/2 values ranged from 60.79 to 76.15 min for TC concentrations varying from 10 to 60 mg/L. Bacterial growth inhibition of Escherichia coli (ATCC 25,922) and Bacillus cereus (ATCC 33,019) were reduced after TC treatment. The study evidenced that using MgO NFs in photodegradation is an effective approach for TC removal from water bodies.

Hierarchical porous carbon nanofibrous membranes with elaborated chemical surfaces for efficient adsorptive removal of volatile organic compounds from air

Volatile organic compounds (VOCs) in the air pose great health risks to humans and the environment. Adsorptive separation technology has proven effective in mitigating VOC pollution, with the adsorbent being the critical component. Therefore, the development of highly efficient adsorbent materials is crucial. Carbon nanofibers, known for their physical–chemical stability and rapid adsorption kinetics, are promising candidates for removing VOCs from the air. However, the relatively simple porous structures and inert surface chemical properties of traditional carbon nanofibers present challenges in further enhancing their application performance further. Herein, a hierarchical porous carbon nanofibrous membrane was prepared using electrospinning technology and a one-step carbonization & activation method. Phenolic resin and polyacrylonitrile were used as co-precursors, with silica nanoparticles serving as the dopant. The resulting membrane exhibited a specific surface area of up to 1560.83 m2/g and surfaces rich in functional O-/N- groups. With a synergistic effect of developed micro- and meso-pores and active chemical surfaces, the carbon nanofibrous membrane demonstrated excellent adsorption separation performance for various VOCs, with comparable adsorption capacities and fast kinetics. Moreover, the membrane displayed remarkable reusability and dynamic adsorption performance for different VOCs, indicating its potential for practical applications.

Coal gasification fine slag derived porous carbon-silicon composite as an ultra-high capacity adsorbent for Rhodamine B removal

The extensive release of industrial solid wastes and organic dyes has led to severe environmental pollution, underscoring the urgent need to recycle these solid wastes and to remove the dyes. Herein, a porous carbon-silicon composite (PC-SiO2) is synthesized using coal gasification fine slag (CGFS) as a precursor via an alkali (KOH) activation and an acid (HCl) etching process, and used as an adsorbent for the Rhodamine B (RhB) removal. The as-synthesized PC-SiO2 possesses an ultra-high specific surface area of 1275.63 m2/g, a large pore volume of 0.26 cm3/g, and enriched reactive functional groups (e.g., Si-OH and –COOH). Due to these features, the actual adsorption capacity and removal ratio of the PC-SiO2 for RhB were as high as 1383.72 mg/g and 92.25 %, respectively, at 298.15 K and pH = 7. Further studies indicate that the adsorption of RhB on PC-SiO2 fits both the pseudo-second-order kinetic model and the Langmuir model, with the maximum equilibrium adsorption capacity being 1388.89 mg/g as predicted by the Langmuir model. The adsorption process involves the electrostatic attraction, hydrogen bonding, π-π interaction, and pore-filling mechanism. This work not only offers a novel approach for removing organic dyes from industrial wastewater but also provides an effective strategy for producing high-value-added materials from industrial solid wastes.

Adsorptive removal of hazardous rhodamine B dye from aqueous solutions by St. John’s wort (Hypericum perforatum)

Adsorptive removal of hazardous rhodamine B dye from aqueous solutions by St. John’s wort (Hypericum perforatum)

One stone two birds: Recycling of an agri-waste to synthesize laccase-immobilized hierarchically porous magnetic biochar for efficient degradation of aflatoxin B1 in aqueous solutions and corn oil

Aflatoxin B1 (AFB1) contamination of oils is a serious concern for the safety of edible oil consumers. Enzyme-assisted detoxification of AFB1 is an efficient and safe method for decontaminating oils, but pristine enzymes are unstable in oils and require modifications before use. Therefore, we designed a novel and magnetically separable laccase-carrying biocatalyst containing spent-mushroom-substrate (SMS)-derived biochar (BF). Laccase was immobilized on NH2-activated magnetic biochar (BF-NH2) through covalent crosslinking, which provided physicochemical stability to the immobilized enzyme. After 30 days of storage at 4 °C, the immobilized laccase (product named “BF-NH2-Lac”) retained ~95 % of its initial activity, while after five repeated cycles of ABTS oxidation, ~85 % activity retention was observed. BF-NH2-Lac was investigated for the oxidative degradation of AFB1, which exhibited superior performance compared to free laccase. Among many tested natural compounds as mediators, p-coumaric acid proved the most efficient in activating laccase for AFB1 degradation. BF-NH2-Lac demonstrated >90 % removal of AFB1 within 5.0 h, while the observed degradation efficiency in corn oil and buffer was comparable. An insight into the adsorptive and degradative removal of AFB1 revealed that AFB1 removal was governed mainly by degradation. The coexistence of multi-mycotoxins did not significantly affect the AFB1 degradation capability of BF-NH2-Lac. Investigation of the degradation products revealed the transformation of AFB1 into non-toxic AFQ1, while corn oil quality remained unaffected after BF-NH2-Lac treatment. Hence, this study holds practical importance for the research, knowledge-base and industrial application of newly proposed immobilized enzyme products.

Highly adsorptive removal of ciprofloxacin and E. coli inactivation using amino acid tryptophan modified nano-gibbsite

Adsorption of essential amino acid, Tryptophan (Tryp) on synthesized gibbsite nanoparticles and their applications in eliminating of antibiotic ciprofloxacin (CFX) and bacteria Escherichia coli (E. coli) in aqueous solution. Nano-gibbsite which was successfully fabricated, was characterized by XRD, TEM-SAED, FT-IR, SEM-EDX and zeta potential measurements. The selected parameters for Tryp adsorption on nano-gibbsite to form biomaterial, Tryp/gibbsite were pH 11, gibbsite dosage 20 mg/mL and 1400 mg/L Tryp. The optimum conditions for CFX removal using Tryp/gibbsite were adsorption time 60 min, pH 5, and 20 mg/mL Tryp/gibbsite dosage. The CFX removal significantly raised from 63 to 90% when using Tryp/gibbsite. The Freundlich and pseudo-second-order models achieved the best fits for CFX adsorption isotherm and kinetic on Tryp/gibbsite, respectively. The amount of CFX increased with increasing ionic strength, suggesting that both electrostatic and non-electrostatic interactions were important. After four reused time, CFX removal was greater than 66%, demonstrating that Tryp/gibbsite is reusable with high performance in removing CFX. The application in bacterial activity in term of E. coli reached greater than 98% that was the best material for bacteria inactivation. The present study reveals that Tryp/gibbsite is an excellent bio-material for removing CFX and E. coli.

ZIF-7-NH2 functionalized collagen fibers for effective and selective mercury ion capture

Adsorptive removal of mercury ion from wastewater has become a hot topic due to the toxicity and persistence; acquiring adsorbent materials with high-capacity, rapid-kinetic, super-selective while low-cost features are highly demanded. Herein, based on the full functionality of collagen fiber (CF) from the leather waste, we proposed an innovative synthetic approach through exploiting amino-functionalized ZIF-7 (ZIF-7-NH2) as functional groups to facilely in-situ incorporate with CF, affording low-cost but effective adsorbent materials of CF/ZIF-7-NH2 composite maximizing both functions of CF and ZIF-7-NH2 in the Hg(II) capture. Remarkably, it exhibits an ultra-high capacity as high as 909.09 mg g-1, fast kinetics that could remove 99.01 % of 200 mg·L-1 within 20 min, and significant selectivity of SHg/M (KdHg/KdM) as large as 522–1017 over Mg2+, K+, Ca2+, Cd2+, and Mn2+. We understand such an impressive adsorption is contributed by the synergistic action between functional groups including on the CF and ZIF-7-NH2. This study offers an effective method for removing heavy metal ions, achieving efficient removal of Hg(II) ions for pollution control, and promoting the reuse of waste CF to reduce waste accumulation in various aspects.

Adsorptive Removal of Organochlorine from Oils by Modified Activated Carbon: Effect of Surface Groups and Kinetic and Thermodynamic Studies

Adsorptive Removal of Organochlorine from Oils by Modified Activated Carbon: Effect of Surface Groups and Kinetic and Thermodynamic Studies

The facile adsorptive removal of commercial grade chlorpyrifos from water using nano-magnetite

The facile adsorptive removal of commercial grade chlorpyrifos from water using nano-magnetite

Tuning strategies of MIL metal organic frameworks for adsorptive removal of formaldehyde in air

Materials Institute Lavoisier (MIL) metal organic frameworks (MOFs) are known for their potential to adsorb gaseous organic pollutants. This study explores the synergistic effects between the selection of central metals (e.g., titanium, iron, and aluminum) and the incorporation of –NH2 groups in terms of adsorption efficiency against gaseous formaldehyde (FA). A group of the pristine MIL MOFs is synthesized using three different metals (i.e., titanium, iron, and aluminum) and terephthalic acid along with their NH2 derivatives using 2-aminoterephthalic acid. Among the pristine forms, MIL-125(Ti) achieves the highest FA adsorption capacity (Q) of 26.96 mg g−1 and a partition coefficient (PC) of 0.0898 mol kg−1 Pa−1. Further, amination significantly improves the FA adsorption potential of NH2-MIL-125(Ti) with a Q value of 91.22 mg g−1 (PC = 0.3038 mol kg−1 Pa−1). In situ diffuse reflectance infrared Fourier-transform spectroscopy reveals that the FA adsorption of plain MILs should be governed primarily by physisorption. In contrast, FA adsorption of NH2-MILs appears to be regulated by both physisorption and chemisorption, while the latter being affected mainly through FA-NH2 interactions (Schiff base reactions). These findings provide valuable insights into the utility of aminated MIL sorbents, possibly toward the efficient management of indoor air quality.

Recent Advances in Ball-Milled Materials and Their Applications for Adsorptive Removal of Aqueous Pollutants

Ball milling, as a cost-effective and eco-friendly approach, has been popular in materials synthesis to solve problems involving toxic reagents, high temperatures, or high pressure, which has the potential for large-scale production. However, there are few reviews specifically concentrating on the latest progress in materials characteristics before and after ball milling as well as the adsorptive application for aqueous pollutants. Hence, this paper summarized the principle and classification of ball milling and reviewed the advances of mechanochemical materials in categories as well as their adsorption performance of organic and inorganic pollutants. Ball milling has the capacity to change materials’ crystal structure, specific surface areas, pore volumes, and particle sizes and even promote grafting reactions to obtain functional groups to surfaces. This improved the adsorption amount, changed the equilibrium time, and strengthened the adsorption force for contaminants. Most studies showed that the Langmuir model and pseudo-second-order model fitted experimental data well. The regeneration methods include ball milling and thermal and solvent methods. The potential future developments in this field were also proposed. This work tries to review the latest advances in ball-milled materials and their application for pollutant adsorption and provides a comprehensive understanding of the physicochemical properties of materials before and after ball milling, as well as their effects on pollutants’ adsorption behavior. This is conducive to laying a foundation for further research on water decontamination by ball-milled materials.

Cysteamine-Anchored MOF through Post-Synthetic Modification Strategy for the Effective Removal of Mercury from Water.

The introduction of cysteamine functionality, referred to as Q-ZIF-67-SH, was successfully achieved through postsynthetic modification while maintaining the structural and thermal stability of the quasi metal-organic framework Q-ZIF-67. By subjecting ZIF-67 to controlled partial deligandation at 310 °C under an air atmosphere, a substantial number of unsaturated cobalt sites were generated within the quasi ZIF-67 (Q-ZIF-67) structure. These unsaturated cobalt sites facilitated effective coordination with cysteamine, resulting in the development of the thiol-functionalized framework Q-ZIF-67-SH. The potential of these metal-organic frameworks (MOFs) for the adsorptive removal of hazardous Hg(II) was investigated. Various factors, such as the type of sorbent, pH, adsorbent dosage, initial concentration of Hg(II), and presence of coexisting ions, were thoroughly examined and comprehensively explained. Thiol-anchored MOF significantly enhanced the efficiency of Hg(II) removal, achieving an impressive removal rate of up to 99.2%. Furthermore, it demonstrated a maximum adsorption capacity of 994 mg g-1 and a distribution coefficient of 2.5 × 106 mL g-1. A good correspondence with pseudo-second-order kinetics and the Langmuir model was observed through the fitting of adsorption kinetics and the isotherm model. The thermodynamic data strongly indicate that the adsorptive removal of Hg(II) is characterized by endothermicity and spontaneity. This signifies that the process is energetically favorable and has potential for efficient Hg(II) removal. Therefore, the Q-ZIF-67-SH sorbent emerges as a promising and advantageous option for the removal of Hg(II) from water.

Efficient adsorptive removal of Sb(Ⅲ) and Sb(V) from printing and dyeing wastewater by TiCl4

Significant amounts of Sb(III) and Sb(V) are present in printing and dyeing wastewater (PDW), which leads to the detrimental effects on the environment if not treated properly. In this paper, the adsorptive removal of Sb(III) and Sb(V) by TiCl4 derived flocs and the oxidation process were investigated. The results showed that TiCl4 conducted superior coagulation performance on Sb(III) removal than Sb(V) in terms of dosage, pH range and immunity to interference. When the dosage was 50 mg/L and the final pH was 5.0, the concentration of Sb(III) and Sb(V) was reduced from 2000 μg/L to 100 μg/L and 180 μg/L, respectively. According to the Langmuir model, The adsorption for Sb(III) (74.27 mg/g) by TiCl4 derived flocs was higher than Sb(V) (68.45 mg/g). The Sb(III) in the solution could partially inhibit the adsorption of Sb(V). It was also observed that the Sb(III) was oxidized to Sb(V), which was owing to the molecular oxygen during the coagulation and the flocs might act as catalyst. The actual printing and dyeing wastewater treatment experiments results showed that pre-reduction of Sb(V) to Sb(Ⅲ) could considerably improve the total Sb removal from 83 % to 98.8 %. The characterization results, such as zeta potential and x-ray photoelectron spectroscopy (XPS), indicated that the Sb(Ⅲ) removal was mainly achieved by chemisorption. The Sb(V) removal was mainly dependent on chemisorption and electrostatic adsorption, while the latter contributed more than former. The results of DFT calculations explained the reason for higher removal efficiencies of Sb(III) than Sb(V) in the TiCl4 coagulation system. This study provides a new idea for the efficient removal of Sb(III) and Sb(V) using TiCl4 in PDW to save the cost in engineering practice.