Efficient Adsorbent For Removal Research Articles

Loofah sponge immobilized ZIF-8 for efficient adsorption removal of U (VI)

Efficient removal of radioactive and toxic uranium (U) from wastewater is highly desired. In this work, a novel adsorbent was prepared via in situ introducing zeolitic imidazolate framework-8 (ZIF-8) onto the hydrolyzed biomass loofah sponge (HLS) for the removal of U (VI). Benefiting from the introduction of ZIF-8, the physical and chemical properties of the composite adsorbent were significantly improved, leading to an enhanced U (VI) adsorption capacity. The results show that the maximum adsorption capacity of the adsorbent toward U (VI) is 244.03 mg/g under the optimal conditions. The adsorption kinetic parameters and isotherm of U (VI) well follow the pseudo second order model and Langmuir model, respectively. Besides, the thermodynamic parameters shows that the adsorption process of U (VI) is a spontaneous process with an exothermic nature. More importantly, the prepared adsorbent has a good reuseability and anti-interference capability during the adsorption of U (VI). This work supplies a new routine to design highly performed adsorbents for the removal of U (VI).

Magnetic hollow fibers of covalent organic frameworks (COF) for pollutant degradation and adsorptive removal

The shaping of covalent organic frameworks (COFs) from non-processible powder forms into applicable architectures with additional functionality remains a challenge. Using pre-electrospun polymer fibers as a sacrificial template, herein, we report a green synthesis of an architecture in the form of COF hollow fibers with an inner layer of peroxidase-like iron oxide nanoparticles as a catalytic material. When compared to peroxidase-like pristine iron oxide nanoparticles, these COF hollow fibers demonstrate higher catalytic breakdown of crystal violet due to their peroxidase-like activity via advanced oxidation process. Furthermore, as a potential adsorbent, hollow COF fibers exhibit significantly effective adsorption capacity and removal efficiency of organic solvent and oil from water. Because of their magnetic nature, COF hollow fibers can be easily recovered and have exhibited high recycling stability for both catalytic dye degradation and organic solvent removal from water.

Loofah sponge immobilized ZIF-8 for efficient adsorption removal of U (VI)

Efficient removal of radioactive and toxic uranium (U) from wastewater is highly desired. In this work, a novel adsorbent was prepared via in situ introducing zeolitic imidazolate framework-8 (ZIF-8) onto the hydrolyzed biomass loofah sponge (HLS) for the removal of U (VI). Benefiting from the introduction of ZIF-8, the physical and chemical properties of the composite adsorbent were significantly improved, leading to an enhanced U (VI) adsorption capacity. The results show that the maximum adsorption capacity of the adsorbent toward U (VI) is 244.03 mg/g under the optimal conditions. The adsorption kinetic parameters and isotherm of U (VI) well follow the pseudo second order model and Langmuir model, respectively. Besides, the thermodynamic parameters shows that the adsorption process of U (VI) is a spontaneous process with an exothermic nature. More importantly, the prepared adsorbent has a good reuseability and anti-interference capability during the adsorption of U (VI). This work supplies a new routine to design highly performed adsorbents for the removal of U (VI).

Synthesis of nano calcium silicates from waste calcite and aragonite phases for efficient adsorptive removal of industrial organic pollutants

The present study focuses on the adsorption efficacy of solid-state synthesized calcium silicate for removing congo red dye. Three different sources were used as calcium precursors; one was calcium carbonate, and the other two were natural waste sources, aragonite (P. globosa) and calcite (Eggshells). Structural analysis and functional groups of the samples were carried out by X-ray diffractometer (XRD), and a Fourier Transform Infrared Spectrometer (FTIR). Various well-known models/equations models such as the Liner Straight Line method of Scherrer’s equation (LSLMSE), Sahadat-Scherrer Model (SSM), Monshi-Scherrer model (MSM), Williamson-Hall model (WHM), Size-Strain plot method (SSP), and Halder-Wagner Model (HWM) were applied to compute the crystallite size of the synthesized calcium silicates; the estimated crystallite size range was 8–77 nm. The adsorption efficacy of the synthesized E-CaSiO3, S-CaSiO3, and C-CaSiO3 was assessed under various provisos for eradicating Congo red dye from wastewater. Computed results revealed that the dye removal percentages were approximately 100 % at 120 min and 200 rpm for 0.2 g E-CaSiO3. The point of zero charge evaluation showed that the pH of the adsorbents during maximum dye removal was 7 and was less than the value of pHpzc. Thermodynamics studies confirmed that the adsorption process was spontaneous. The method of adsorption of dye by the adsorbent was more clearly comprehended by Langmuir, Freundlich, and Temkin adsorption isotherm. 151.28 mg/g was the maximum adsorption capacity for S- CaSiO3 depending on the Langmuir isotherm model’s linear form (R2 = 0.924).

Synthesis and Characterization of Graphene Oxide for Efficient Adsorptive Removal of Hymexazol Pesticide from Aqueous Solutions: Thermodynamic, Kinetic, and Isotherm Studies

Background: Nanomaterials play a significant role in the field of water treatment due to their environment-friendly and appealing physical and chemical characteristics. Objective: The purpose of this research is to evaluate whether graphene oxide adsorbents can effectively remove hymexazol pesticide from an aqueous solution. Methods: Graphene oxide (GO) was prepared by the modified Hummer method, and it was characterized by a number characterization techniques, including XRD, Raman spectroscopy, FE-SEM, TEM, and EDX. Furthermore, the performances of the GO adsorbents for the removal of hymexazol from aqueous solution were investigated. The effect of contact time, GO dosage, initial hymexazol concentration, and temperature was carefully studied. Results: The kinetic experimental data were best described by the pseudo-second-order kinetic model. The equilibrium data were well fitted by the Freundlich and Langmuir isotherm models. The kinetic experimental data were best described by the pseudo-second-order kinetic model. And through the thermodynamic studies, it was found that the adsorption process of hymexazol pesticide is endothermic and spontaneous, in addition to the occurrence of adsorption and absorption together. Conclusions: The findings of the adsorption process demonstrated that graphene oxide is an extremely efficient adsorbent material for pesticide adsorption, owing to its large surface area and the presence of oxygen-rich groups on its surface.

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.

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.

Enhanced adsorption and visible-light photocatalytic degradation of CIP by CdS QDs‐Decorated Mn-doped NH2-UiO-66

CdS Quantum dots (QDs) interspersed on the surface of Mn-UiO-66-NH2 (hereafter abbreviated as CdS QDs@Mn-UiO-66-NH2) Z-scheme heterojunction composites were synthesized by solvothermal method for the removal of ciprofloxacin (CIP) under visible light irradiation. The influences of the doping content of Mn and the initial concentrations of CIP on the adsorption capacity and photocatalytic performance were investigated in detail. Compared to the pristine CdS and Mn-UiO-66-NH2, the fabricated CdS QDs@Mn-UiO-66-NH2 composites exhibited enhanced adsorption and photocatalytic capabilities, especially for the CMU-5 with 10 % Mn doping showing around 52.5 % adsorption removal efficiency and about 92 % photocatalytic removal efficiency for CIP (30 mg/L). Various technologies such as XPS, TG and UV–vis DRS have confirmed that the superior catalytic performance of CMU-5 is ascribed to the d-d transitions improving the utilization of visible light after the coordination of the transition metal and the presence of a heterojunction with a tight interfacial structure enhancing the charge transfer. The possible intermediates in the photodegradation process of CIP were detected using gas chromatography-mass spectrometry (GC-MS).

Efficient adsorptive removal of 2,4-dichlorophenoxyacetic acid (2,4-D) using biomass derived magnetic activated carbon nanocomposite in synthetic and simulated agricultural runoff water

This study focused on evaluating the efficacy of a magnetic activated carbon material (CPAC@Fe3O4) derived from pods of copper pod tree in adsorbing the toxic herbicide, 2,4- (2,4-D) from aqueous solutions. The synthesized CPAC@Fe3O4 adsorbent, underwent various characterization techniques. FESEM images indicated a rough surface, incorporating iron oxide nanoparticles, while EDS analysis confirmed the presence of elements like Fe, O, and C. Notably, the CPAC@Fe3O4 exhibited high surface area (749.10 m2/g) and pore volume (0.5351 cm³/g), confirming its mesoporous nature. XRD investigations identified distinct signals associated with graphitic carbon and magnetite nanoparticles, while VSM analysis verified its magnetic properties with a high magnetic saturation value (2.72 emu/g). The adsorption process was exothermic, with a decrease in adsorption capacity at higher temperatures. Freundlich isotherm provided the best fit for the adsorption, and the pseudo-second-order equation effectively described the kinetics. Remarkably, the maximum adsorption capacity ranged from 246.43 to 261.03 mg/g, surpassing previously reported values. The ΔH° value (−8.67 kJ/mol) suggested a physisorption mechanism, and the negative ΔG° values established the spontaneous nature. Furthermore, the synthesized adsorbent demonstrated exceptional reusability, allowing for up to five cycles of adsorption-desorption operations. When applied to simulated agricultural runoff, CPAC@Fe3O4 showcased a significant adsorption capacity of 160.71 mg/g for 50 mg/L 2,4-D, using a 0.2 g/L dosage at pH 2. This study showcased the transformation of copper pod biomass into a valuable magnetic nanoadsorbent capable of efficiently eliminating the noxious 2,4-D pollutant from aqueous environments.

Evaluating the effectiveness of heavy metals removal from mine wastewater using agricultural waste materials

Polluted water bodies pose a danger to both aquatic and terrestrial lives, and recent development in the mining centre has escalated this pollution through the disposal of its industrial wastes. The objective was to investigate the potential of four different agricultural waste materials in eliminating the heavy metals from mine wastewater. The results show that the best performance in terms of adsorption capacity and removal efficiency was observed with coconut husk-activated carbon. The Arsenic (As) concentration decreased from 3.185 mg/kg to 1.570 mg/kg, and the Mercury (Hg) content decreased from 0.0307 mg/kg to 0.0064 mg/kg. The corresponding removal efficiencies were 51% for Arsenic and 79% for Mercury after 120 minutes of contact time at a speed of 250 rpm. The results suggest that coconut husk-activated carbon exhibited superior adsorption capacity and removal efficiency compared to the other agricultural waste materials (maize cob, rice husk, and sawdust). This indicates that the natural properties of coconut husk are more effective in removing heavy metals from mine wastewater.

Construction of attapulgite decorated cetylpyridinium bromide/cellulose acetate composite beads for removal of Cr (VI) ions with emphasis on mechanistic insights

Eco-friendly and renewable composite beads were constructed for efficient adsorptive removal of Cr (VI) ions. Attapulgite (ATP) clay decorated with cetylpyridinium bromide (CPBr) was impregnated into cellulose acetate (CA) beads, which were formulated through a simple and cost-effective solvent-exchange approach. FTIR, XRD, SEM, Zeta potential, and XPS characterization tools verified the successful formation of ATP–CPBr@CA beads. The composite beads displayed a spherical and porous shape with a positively charged surface (26.6 mV) at pH 2. In addition, higher adsorption performance was accomplished by ATP–CPBr@CA composite beads with ease of separation compared to their components. Meanwhile, equilibrium isotherms pointed out that the Langmuir model was optimal for describing the adsorption process of Cr (VI) with a maximal adsorption capacity of 302 mg/g. Moreover, the D–R isotherm model verified the physical adsorption process, while adsorption data obeyed the pseudo-second-order kinetic model. Further, XPS results hypothesized that the removal mechanism involves adsorption via electrostatic interactions, redox reaction, and co-precipitation. Interestingly, the ATP–CPBr@CA composite beads reserved tolerable adsorption characteristics with a maximum removal present exceeding 70% after reuse for seven successive cycles, proposing its feasible applicability as a reusable and easy-separable candidate for removing heavy metals from aquatic bodies.

Efficient Adsorption Removal of Tetrabromobisphenol A from Water by Using a Magnetic Composite Fe3O4/GO/ZIF-67

Tetrabromobisphenol A (TBBPA) is a kind of widely used brominated flame retardant (BFR), which is proven to be harmful to ecological systems and public health. It is very important to remove TBBPA from the environment. In our study, a magnetic composite named Fe3O4/GO/ZIF-67 was synthesized by a coprecipitation method and applied in the highly efficient adsorption of TBBPA from water. Static adsorption experiments demonstrated that the adsorption capacity could reach 232 mg·g−1 within 120 min, which is much higher than those reported in the other literature. The experimental results show that the adsorption of TBBPA on Fe3O4/GO/ZIF-67 followed Langmuir and pseudo-second-order kinetic adsorption models. The main mechanisms for these adsorptions were identified as hydrogen bonds between OH groups in TBBPA and COOHs of Fe3O4/GO/ZIF-67, and π-π stacking between Fe3O4/GO/ZIF-67 and TBBPA. This study provides a method with great promise for the design and synthesis of better adsorbents for the removal of TBBPA from the water environment.

When covalent organic frameworks meet zeolites: Enhancing rhodamine B removal through the synergy in the emerging organic–inorganic nanoadsorbents

The development of new porous materials has attracted intense attention as adsorbents for removing pollutants from wastewater. However, pure inorganic and organic porous materials confront various problems in purifying the wastewater. In this work, we integrated a covalent organic framework (TpPa-1) with an inorganic zeolite (TS-1) for the first time via a solvothermal method to fabricate new-type nanoadsorbents. The covalent organic framework/zeolite (TpPa-1/TS-1) nanoadsorbents combined the merits of the zeolite and COF components and possessed efficient adsorptive removal of organic contaminants from solution. Structural morphology and chemical composition characterization by powder X-ray diffraction, scanning electron microscopy, Fourier-transform infrared spectroscopy, X-ray photoelectron spectroscopy, transmission electron microscopy and thermogravimetric analysis demonstrated the successful preparation of TpPa-1/TS-1 composite nanoadsorbents. The resultant composite adsorbent TpPa-1/TS-1 removed rhodamine B at 1.7 and 2.6 times the efficiency of TpPa-1 and TS-1, respectively. Additional investigation revealed that the Freundlich adsorption isotherm and the pseudo-second-order kinetic model could be employed to represent the adsorption process more appropriately. Thermodynamic calculation analysis showed that the adsorption process proceeded spontaneously and exothermically. Besides, the effects of pH, absorbent mass and ionic strength on the adsorption performance were systematically investigated. The prepared composite adsorbent showed a slight decrease in removal efficiency after eight cycles of repeated use, and real water environment experiments also showed the high stability of the adsorbent. The enhanced performance can be attributed to electrostatic interaction, acid-base interaction, hydrogen bonding and π–π interactions.

A novel peony-shaped ZnO/biochar nanocomposites with dominant {100} facets for efficient adsorption and photocatalytic removal of refractory contaminants

Herein, a peony-shaped nanocomposite (P-ZnO/BC) was facilely developed by incorporating ZnO with Hemp stalk derived biochar (BC) via two-step sequential solvothermal procedure and used for photocatalytic degradation of organic contaminants. The as-prepared P-ZnO/BC presents preferential (100) crystal orientation, suitable electronic energy level, and distinct mesoporous distribution as well as large specific surface area. Thereby, the optimal P-ZnO0.3/BC (weight ratio of 3:7 for ZnO:BC) shows higher photocatalytic activity with degradation efficiency as high as 94.5 % toward methylene blue (MB) within 120 min, whereas the ZnO and BC merely deliver 6.3 % and 63.5 %, respectively. Obviously, the superior contaminants removal properties of P-ZnO0.3/BC can be attributed to the synergistic effect of adsorption of BC and photocatalysis of ZnO. Also, this can be associated with the improved adsorption, accelerated charges (e-/h+ pairs) transportation and reduced e-/h+ pairs recombination of P-ZnO0.3/BC. The reactive radicals scavenging experiments and ESR measurements confirm that the main reactive species are hydroxyl radicals (•OH) and holes (h+). Furthermore, P-ZnO0.3/BC displays desirable reusability and better universal applicability toward other organic dyes and antibiotics removal. Moreover, the possible degradation mechanism and pathway were also inferred by analyzing the intermediates via liquid chromatography mass spectrometry (LC-MS) technique. In conclusion, this work provides a fundamental insight via integrating ZnO with low-cost BC for efficient removal of the refractory organic pollutants.

One-pot growth and characterization of α-Fe2O3/β-FeOOH micro-nanosystem for industrial dye removal

A micro-nanosystem of α-Fe2O3/β-FeOOH was developed for the first time using a one-pot hydrothermal method. The synthesis mechanism of the simultaneous development of micro-sized α-Fe2O3 and nano-sized β-FeOOH is discussed. The structural properties studied via X-ray diffraction (XRD) revealed the presence of both phases, whereas the FESEM study confirms that α-Fe2O3 and β-FeOOH are of microdisc and nanohusk type, respectively. Considering the two different shapes and sizes of particles in a micro-nanosystem, α-Fe2O3/β-FeOOH was used to remove rhodamine B dye. The hydrogen bonding between the adsorbent and the RhB dye influences the binding properties. The mixed-shaped iron-based particles have provided maximum adsorbing sites which have strengthened the bonding between the adsorbent and adsorbate. The FTIR study was used to confirm the binding of RhB dye with the micro-nanosystems. Adsorption capacity and removal efficiency for α-Fe2O3/β-FeOOH micro-nanosystem adsorbent were found to be 727 mg g−1 and 91 % respectively. The binding mechanism along with the adsorption isotherm and adsorption kinetic study, has been discussed. The adsorption isotherm study confirms that the adsorption process followed the Freundlich isotherm model. The adsorption kinetic study suggested the well-fitting of pseudo-first-order kinetics and the Elovich model with the adsorption process. The reusability study of the micro-nanosystem confirms that the micro-nano system can retain the highest removal efficiency up to 4th cycle. Further, the fabricated micro-nanosystem was applied for the removal of RhB dye from the real water samples, collected from different sources.

Ternary heterojunction of cross-linked benzene Polymer/Bi2MoO6-Graphene oxide catalysts promote efficient adsorption and photocatalytic removal of oxytetracycline

Antibiotics are refractory degradable organic pollutants that present a significant hazard to water environments. In this work, a ternary composite (KB/BMO-GO) comprising of graphene oxide (GO), Bi2MoO6 (BMO), and a cross-linked benzene polymer (KB) was synthesized and applied to promote the synergistic adsorption-photocatalytic degradation of the refractory pollutant, oxytetracycline (OTC). The inclusion of GO and KB in the composite enhanced the OTC adsorption performance of the catalysts, and the construction of Z-scheme heterojunction promoted the photogenerated charge separation efficiency and broadened the range of light absorption, thereby enhancing the photocatalytic performance. Moreover, we compared the performance of catalysts loaded with different mass ratios of KB (x% KB/BMO-GO). Among them, the 15 % KB/BMO-GO catalyst sample had the best OTC degradation performance. Specifically, 15 % KB/BMO-GO could adsorb 69.7 % of OTC in 30 min, reaching an OTC degradation rate of 93.3 % under visible light irradiation. h+ and 1O2 are the main active substances in the photocatalytic process. In addition, the catalysts are acid-alkali and salt-resistant, as well as good reusability. This study provides a valuable reference for the preparation of highly efficient photocatalysts for synergistic adsorption-photodegradation processes.

The absorption effect and mechanism of graphene oxide removal from aqueous solution by basalt stone power

Graphene oxide (GO) is a novel carbon material utilized extensively for diverse industrial applications. When exposed to environmental elements like sunlight and chlorination, GO can undergo a series of physical and chemical transformations, and its presence in water and the environment can endanger ecosystems. Therefore there is a need for methods that can effectively remove GO from water. Accordingly, we delve into the efficacy of basalt stone powder (BSP) as an adsorption medium for purifying aqueous solutions of GO. We examine the impact of various experimental parameters—namely pH, initial solution concentration, adsorbent mass, contact duration, and ambient temperature—on GO adsorption, employing the method of controlled variables. The adsorption efficacy is notably influenced by the pH level. At an acidic pH of 3, an initial GO concentration of 80 mg/L, an adsorbent dosage of 50 mg, and a temperature of 303 K (approximately 30 °C), the adsorption removal efficiency reaches an impressive 99 %, boasting a maximum adsorption capacity of 112 mg/g. Dynamically, the adsorption kinetics align most closely with a pseudo-first-order model, achieving equilibrium after 24 h. Thermodynamic analyses reveal that the Langmuir isotherm model most accurately describes the adsorption behavior, indicating an enhancement in BSP's adsorption capacity for GO as temperature rises. Based on thermodynamic equations, the adsorption of GO onto BSP is deduced to be a spontaneous process. Our findings illustrate BSP's considerable potential in the treatment and removal of GO from water, and therefore it may prove useful in environmental remediation efforts.

A Laboratory Investigation of the Adsorption Performance and Mechanism of Organics in Industrial Wastewater on mp-Zr(OH)4

We reported on the development of mesoporous zirconium hydroxide (mp-Zr(OH)4) sorbents with high capacity for adsorptive removal of organic pollutants from industrial wastewater. The sorbent was prepared by a one-step chemical precipitation method at room temperature. The adsorption capacity and removal efficiency for the chemical oxygen demand (COD) of the industrial wastewater were studied using an automatic adsorption measurement apparatus. The effects of different parameters (adsorbent dosage, adsorption time, regeneration times, adsorbate's molecular weight and adsorbate solubility), isotherm, thermodynamics, and kinetics were evaluated. By analyzing scanning electron microscopy (SEM) images and powder X-ray diffractograms (XRD) no obvious differences were observed for the sorbents before and after the adsorption of the organics, which indicated a structural stability of the sorbent. The specific surface area was reduced from 450 m2/g to 189 m2/g on adsorption, and after desorption of the organics the specific surface area was 350 m2/g. The adsorption of COD was analyzed in a Langmuir model that described the data better than the empirical Freundlich model. This finding points towards that the adsorption occurred as a monolayer on the mp-Zr(OH)4. The free energy of adsorption (ΔG) is in the range of −20 kJ/mol < ΔG < 0. Entropy changes are ΔS > 0. The kinetics of the adsorption of COD is better described with a Quasi-second-order dynamic model than with a Quasi-first-order dynamic model, which elucidates its primary reliance on porous adsorption surfaces and incorporation of chemical adsorption.

Post-modified linker functionalization of metal organic frameworks for high-efficiency adsorption and quantification of trace organophosphorus pesticides in environmental water

Water pollution caused by organophosphorus pesticides (OPPs) from agricultural production causes vital great threat to mankind lives and thus developing a method for rapid removal and detection of OPPs is urgent. In this work, we proposed the linker functionalization of metal organic frameworks (UiO-66) by post-modification to generate defects and active sites for tailoring their adsorption behavior. The metal organic frameworks (MOFs) modified by functional groups (amino and pyridine) exhibited similar physicochemical property and pore structure. The UiO-66-PA exhibited an excellent performance of rapid adsorption of OPPs in water with average capacity of 246.55 mg/g. Experimental characterizations and theoretical simulations revealed that the enhanced binding energy between UiO-66-PA and OPPs resulted from synergistic interaction between pyridine and OPPs via nucleophilic effect, π-π interaction, and metal electronic interaction, boosting the adsorption capacity and removal efficiency, which suggested that functional group plays important role in improving performance. When used it as adsorbent for analysis of OPPs in water coupled with ambient ionization source, UiO-66-PA exhibited an excellent performance of the quantitative detection of OPPs in water with limit of detections (LODs) of 0.076–––0.251 ng/mL and relative standard deviations (RSDs) of 1.13 % − 5.84 %. In addition, the proposed analytical method could be applied in analysis of three environmental water samples with great sensitivity, anti-interference and reusability, which demonstrated that UiO-66-PA afforded outstanding selectivity for OPPs and could be appropriate for high-throughput screening and on-site analysis. This work could provide a novel method to design MOFs-based adsorbents with functions of removal and purification via post-modification and exhibit a great potential to rapid analysis of OPPs in environmental water.

Poly(2-hydroxyethyl methacrylate)/BN nanohybride: Enhanced adsorption of antibiotic pollutant removal from wastewater

Increasing wastewater pollution by pharmaceutical waste poses a serious threat to environmental safety and public health, so sorbents with high adsorption capacity and removal efficiency are in high demand. To address this important problem, a novel pellet sorbent containing (2-hydroxyethylmethacrylate)-modified BN nanoparticles (pHEMA/BN) was produced by a combination of CVD synthesis (BN), solution method (pHEMA/BN nanoparticles) and uniaxial pressing (pHEMA/BN pellets) and studied for the adsorption of tetracycline (TC) and linezolid (LNZ) from aqueous solutions. Characterization techniques, including scanning electron microscopy, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy, have provided insight into adsorbent microstructure and specific surface area. At an initial antibiotic concentration of 100 mg/L, pHEMA/BN adsorbent demonstrated an 84–88 % increase in equilibrium adsorption capacity after 24 h and an 86–89 % increase in antibiotic removal efficiency compared to unmodified BN. Molecular dynamics calculations revealed robust interactions between the polymer and BN, accompanied by an electron density redistribution. And density functional theory calculations showed the formation of multiple hydrogen bonds between the polymer hydroxyl groups and the antibiotic functional groups. Adsorption kinetics analysis suggested that pHEMA/BN adsorption involves both physical interaction and chemisorption. The pHEMA/BN material demonstrates good reusability with an adsorption efficiency >90 % after three sorption cycles with sorbent regeneration between cycles. These results highlight the high potential of pHEMA/BN adsorbents for practical applications in drinking water and wastewater treatment, offering versatility and efficiency in the pharmaceutical contaminant adsorption, thereby facilitating the development of more cost-effective and sustainable wastewater treatment methods compared to conventional adsorbents.