Hg Adsorption Research Articles

Novel enhancement strategy for Hg adsorption in wastewater: Nonthermal plasma-mediated advanced modification of zero-valent iron-carbon galvanic cells with thiol functionalization.

Mercury (Hg) pollution poses a critical threat to human health and the environment, necessitating urgent control measures. This study introduces a novel modification method for the common zero-valent iron-carbon (ZVI-AC) galvanic cells using a two-step process, nonthermal (NTP) irradiation followed by targeted functionalization, aiming to enhance Hg adsorption potential by adjusting the physicochemical properties of the cells. The NTP irradiated functionalized adsorbent demonstrated superior Hg adsorption performance across various concentrations and pH variations. Multichannel adsorption mechanisms were confirmed by fitting a total of 22 different adsorption isotherm models, indicating the coexistence of monolayer and multilayer adsorption processes. The NTP irradiation modifies the ZVI and AC, inducing nitrogen and oxygen doping on carbon-based surfaces and oxidizing ZVI to Fe(II)-Fe(III) species. The deepened oxidation of Fe in NTP-Fe-C, coupled with Hg2+ reduction to elemental Hg by raw Fe, contributed to Hg removal. NTP irradiation facilitated electron transfer between Fe and Hg, promoting oxidation of Fe and reduction of Hg2+ cations. The emergence of diverse Hg species further supported the multichannel adsorption/removal mechanism achieved by NTP-irradiated cells. This method offers a promising solution to Hg pollution and expands the application of the traditional iron-carbon galvanic cells in treating hazardous heavy metal wastes.

Tunable porosity and Hg (II) adsorption performance in dual heteroatom functionalized conjugated micro-mesoporous poly(aniline)s

Tunable porosity and Hg (II) adsorption performance in dual heteroatom functionalized conjugated micro-mesoporous poly(aniline)s

Natural cellulose fibers from Agave Americana L. ASPARAGACEAE as an effective adsorbent for mercury in aqueous solutions

This study investigated the use of functionalized cabuya fibers (FCF) as an effective adsorbent for Hg (II) removal from aqueous solutions. The composition, surface properties, and morphology of the FCF were characterized by scanning electron microscopy (SEM), energy dispersive X-ray spectrometry (EDS), and Fourier transform infrared spectroscopy (FTIR). The effects of the pH, contact time, temperature, adsorbent dosage, and initial Hg (II) concentration on the adsorption process were studied. Under optimized experimental conditions, FCF achieved a removal efficiency exceeding 92%, with a maximum adsorption capacity of 8.29 mg/g. The experimental data for the FCF isotherm were analyzed using the Langmuir, Freundlich, DR, and Temkin adsorption models. Notably, the Langmuir isotherm exhibited the highest R² value of 0.99, indicating the model’s strong applicability. The pseudo-second-order kinetic model k2 = 0.42 mg/g.min was employed to elucidate the adsorption mechanism. Thermodynamic studies of the adsorbent FCF were conducted, and ΔG° (-6.16 kJ/mol), ΔH° (36.29 kJ/mol), and ΔS° (141.98 kJ/mol·K) were calculated, assessing the feasibility of the process. Additionally, the desorption results of FCF were evaluated, demonstrating that it can be reused for up to three cycles, achieving adsorption rates of 74% and 62% in the third cycle. This indicates its stability and recycling capacity. Finally, the effectiveness of the FCF was demonstrated by eliminating approximately 91% of Hg (II) from real mineral water samples in Ecuador. These results highlight the p of FCF as promising, eco-friendly, and sustainable adsorbents for the remediation of Hg (II) contamination in aquatic systems.

NiFe2O4/g- C3N4 modified chitosan Schiff base composite for efficient removal of Cu(II) and Hg(II) ions from the aquatic environment and its antibacterial properties

Modification of chitosan has been achieved by the reaction of chitosan with 4- nitro-benzaldehyde via the sol-gel method, resulting in a Schiff base. A novel magnetic Graphitic Carbon Nitride/chitosan-Schiff base/NiFe2O3 (SBIV@NiFe/g-C3N4) adsorbent was synthesized by hydrothermal route for the adsorption of Cu(II) and Hg(II) ions from the aquatic environment. The synthesized SBIV@NiFe/g-C3N4 was characterized using infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), vibrating sample magnetometer (VSM), and Brunauer-Emmett-Teller (BET), with a surface area of approximately 13.657 m2/g. It was anticipated by the results that magnetic SBIV@NiFe/g-C3N4 would be effectively synthesized. On Cu(II) and Hg(II) adsorption, the impacts of significant variables, including pH solution, contact duration, metal ion concentration, adsorbent dosage, and co-existing ions, were examined. Under ideal circumstances, the optimum adsorption capacities of Cu(II) and Hg(II) ions were 889.76 mg/g and 703.21 mg/g, respectively. Furthermore, the SBIV@NiFe/g-C3N4 material exhibited the beneficial property of simple separation, permitting the continuation of high removal effectiveness for heavy metals like Cu (II) and Hg(II) despite experiencing many reuse cycles. In summary, there are a lot of opportunities for the effective elimination of Cu (II) and Hg (II) from different water sources shortly with the use of SBIV@NiFe/g-C3N4, a new adsorbent. The as-synthesized SBIV@NiFe/g-C3N4 displayed better antibacterial activity against highly lethal bacteria like S. aureus and P. vulgaris.

UV-Aged Nanoplastics Increase Mercury Toxicity in a Marine Copepod under Multigenerational Exposure: A Carrier Role.

Aged plastics possess diverse interactive properties with metals compared to pristine ones. However, the role of aging for nanoplastics (NPs) in being a carrier of mercury (Hg), a common marine environmental pollutant, and their combined effects remain unclear. This study investigated the carrier effect of ultraviolet-aged NPs on Hg and the ensuing toxicity in a marine copepod Tigriopus japonicus under a multigenerational scenario. Aged NPs revealed a better carrier role in Hg bioaccumulation than pristine ones, which was increased by 1.61, 1.52, and 1.54 times in F0, F1, and F2, respectively, probably attributed to increased levels of O-containing functional groups and better adsorption for Hg. Consequently, relative to Hg alone, Hg combined with aged NPs (rather than pristine ones) significantly compromised the copepod's fitness, e.g., the survival rate decreasing by 74.2 and 62.1% in F1 and F2, respectively. This is possibly linked to the most pronounced transcriptomic response under Hg combined with aged NPs, including disturbed cuticle formation, activated antioxidants, and down-regulation of reproductive genes. Overall, our findings emphasize the non-negligible risk of aged NPs as carriers of toxic metals and provide a better understanding about the long-term effects of coexisting NPs and metal pollution on organisms in real marine environments.

Study on the Desorption Mechanism of Sulfur Dioxide–Modified Activated Carbon Based on Density Functional Theory

ABSTRACTActivated carbon injection technology is the primary method used to control the mercury emissions from coal‐fired power plants. The preparation of sulfur‐loaded carbon‐based adsorbents through SO2 modification of the surface of activated carbon (the primary component) provides an effective solution to enhancing the mercury removal performance of adsorbents. However, there remains a lack of clarity on the adsorption performance and mechanism of mercury on the newly formed active sites of the carbon surface after SO2 sulfur loading modification. In this study, four potential structures of SO2 loaded onto the surface of activated carbon were constructed. Quantum chemical calculation methods were applied to calculate the adsorption process of Hg in these four models, with those important characteristics identified such as bonding properties, adsorption energy, electrostatic potential, and molecular orbitals. As indicated by those results, the adsorption bonds of the SO2‐modified activated carbon were mainly C‐O‐S and C‐S‐C. After the carbon cluster model adsorbed SO2 molecules, the sulfur in SO2 exhibited a strong positive potential that facilitated the loss of electrons from Hg due to the potential difference. Consequently, HgO was firmly adsorbed onto the surface of the carbon cluster. As revealed by the molecular orbital calculations performed after Hg adsorption on the two carbon cluster models, SO2‐modified and elemental sulfur‐modified activated carbons, in the SOAC‐Arm‐1 configuration, there was a clear exchange orbital around the adsorbed Hg atom in the LUMO, with a small HOMO–LUMO energy gap of only 0.01713 eV. At this point, the free electrons on the molecule were prone to orbital transitions, promoting the occurrence of adsorption reactions. The SOAC‐Arm‐3 conformation exhibited the shortest C‐Hg bond length and had an adsorption energy of up to −70.42 kJ/mol, indicating a stronger chemical bonding ability and a higher likelihood of adsorption reactions. These results demonstrate the feasibility of sulfur‐loaded modified activated carbon to mitigate Hg pollution through SO2.

Interweaving two dimensional mesoporous covalent organic frameworks for efficient removal of mercury from aqueous solution

Interweaving two dimensional mesoporous covalent organic frameworks for efficient removal of mercury from aqueous solution

Facile Doping and Functionalization of Molybdic Acid into Nanobiochar to Enhance Mercury Ion Removal from Water Systems.

Functionalized nanomaterials with surface-active groups have garnered significant research interest due to their wide-ranging applications, particularly in water treatment for removing various contaminants. This study focuses on developing a novel, multi-functional nanobiosorbent by synthesizing nanosized biochar from artichoke leaves (NBAL) and molybdic acid (MA). The resulting nanobiosorbent, MA@NBAL, is produced through a microwave-irradiation process, offering a promising material for enhanced environmental remediation. The characteristics of assembled MA@NBAL were evaluated from SEM-EDX, XPS, TGA, FT-IR, and zeta potential detection. The size of particles ranged from 18.7 to 23.7 nm. At the same time, the EDX analysis denoted the existence of several major elements with related percentage values of carbon (52.9%), oxygen (27.6%), molybdenum (8.8%), and nitrogen (4.5%) in the assembled MA@NBAL nanobiosorbent. The effectiveness of MA@NBAL in removing Hg(II) ions was monitored via the batch study method. The optimized maximum removal capacity of Hg(II) ions onto MA@NBAL was established at pH 6.0, 30.0 min equilibrium time, and 20 mg of nanobiosorbent, providing 1444.25 mg/g with a 10.0 mmol/L concentration of Hg(II). Kinetic studies revealed that the adsorption process followed a pseudo-second-order model, with R2 values ranging from 0.993 to 0.999 for the two tested Hg(II) concentrations, indicating excellent alignment with the experimental data. This suggests that the chemisorption mechanism involves cation exchange and complex formation. Isotherm model evaluation further confirmed the adsorption mechanism, with the Freundlich model providing the best fit, yielding an R2 of 0.962. This result indicates that Hg(II) adsorption onto the surface of MA@NBAL nanobiosorbent occurs on a heterogeneous surface with multilayer formation characteristics. The results of the temperature factor and computation of the thermodynamic parameters referred to endothermic behavior via a nonspontaneous process. Finally, the valid applicability of MA@NBAL nanobiosorbent in the adsorptive recovery of 2.0 and 5.0 µg/mL Hg(II) from contaminated real aquatic matrices was explored in this study, providing 91.2-98.6% removal efficiency.

Novel optical optode for selective detection and removal of ultra-trace level of mercury ions in different environmental real samples

Owing to the high cost and unavailability of different analytical techniques, there is an urgent need to develop new techniques not only for detecting but also removing mercury ions in real samples. Thus, an optical chemical sensor based on the anchoring of phenanthraquinone monophenylthiosemicarbazone in a plasticized cellulose triacetate membrane was fabricated and applied to the recognition and removal of mercury ions from aqueous solutions. The synthesized optode was characterized by FT-IR, SEM, AFM, and thermal analysis. Several parameters, including the pH, temperature, contact time, washing solvent, and washing time, were optimized. Under optimal conditions, a promising optode film platform was utilized for sensing mercury ions, and the concentrations were calculated based on colorimetric analysis (Histogram, RGB) of digital images, visualization, and spectrophotometry. Also, an optical optode was used for complete adsorption of mercury ions from aqueous solutions. In addition, the regeneration of the synthesized optode was evaluated using 0.1 mol L− 1 nitric acid, which effectively removed all adsorbed mercury ions. The obtained data indicated good linearity in the sensing and adsorption of Hg2+ over a concentration range of 0.005–5000 µgL− 1 with a low limit of detection (LOD = 0.066 µgL− 1) and limit of quantification (LOQ, 0.22 µgL− 1). Furthermore, it showed good distinctions in the presence of coexisting ions, high stability (five months), good applicability, and reproducibility (RSD = 1.31%), making it a promising sensor for Hg2+ detection. On the other hand, the kinetic studies revealed that the pseudo-second-order was the best model for describing the adsorption behavior of mercury ions on the optode surface. Also, the thermodynamic parameters indicate spontaneous (ΔG0 < 0) and endothermic (ΔH0 < 0) reactions. Also, the maximum adsorption capacity was found to be 73.2 mg g− 1. Thus, the optodes were successfully applied for the detection and/or removal of Hg2+ in different real samples, including cucumber, fish, soil, and water samples, with excellent recoveries of 98.1–99.5%.

Melamine-Derived Mesoporous Carbon for Efficient and Selective Removal of Trace Hg(II) from Honeysuckle Decoction.

Melamine-derived mesoporous carbon, which was obtained from pyrolysis of modified melamine, was employed for the purpose of eliminating trace amounts of Hg(II) from honeysuckle decoction. The specific surface area of the mesoporous carbons with N-functional (MCN1) was 648.372 m2·g-1. The chemical composition and morphology of MCN1 were thoroughly examined, and a comprehensive analysis led to the identification of its formation mechanism. A noteworthy association has been identified between the adsorption efficacy and the chemical composition of MCN1. In the elimination of trace mercury in aqueous solutions over a broad pH range (pH 2-9), MCN1 demonstrates high effectiveness, approaching 100%. Adsorption kinetics and isotherm results indicate that a more accurate representation of Hg(II) adsorption on MCN1 is provided by pseudo-second-order kinetics and Freundlich models, with chemical adsorption being the dominant mechanism. This study further examined the removal of chlorogenic acid, a bioactive component, by MCN1. The findings imply that MCN1 has a noteworthy 80% efficacy in removing mercury from honeysuckle decoction while maintaining the purity of its medicinal ingredients, particularly chlorogenic acid. As a result, utilizing MCN1 for the adsorption of Hg(II) in honeysuckle decoction appears to be a reasonable approach.

Efficient Adsorption of Hg(II) Ions Benefits from the Synergistic Effect between Sulfur-Containing MOF-808 and C3N4

Efficient Adsorption of Hg(II) Ions Benefits from the Synergistic Effect between Sulfur-Containing MOF-808 and C3N4

Plasma-induced aging of microplastics and its effect on mercury transport and transformation

Plasma-induced aging of microplastics and its effect on mercury transport and transformation

Research on Activation Mechanisms In Situ during Rapid Desorption of Mercury-Absorbing Activated Coke by the Heating Method.

The adsorption of active coke is a good method to control mercury in coal-fired power plants, but spent powdered activated coke (SPAC) will cause secondary pollution and waste of resources if it is not properly treated. The purpose of this study was to explore the desorption performance of SPAC when heated in a drop-tube reactor under different atmospheres. The carbon consumption was 0.13%, 0.24%, 0.17%, 0.16%, and 0.14%, under desorption conditions in N2, O2, H2O, CO2, and SFG (N2 + 12% CO2 + 6% H2O + 6% O2) atmospheres, respectively. The readsorption performances of PAC-N2, PAC-CO2, PAC-H2O, PAC-O2, and PAC-SFG were 40%, 72%, 77%, 58%, and 86%, respectively. In particular, compared with the original PAC, the physicochemical properties of PAC-SFG (optimum conditions) changed greatly; the surface area of PAC-SFG and the pore volume increased by 14.1% and 11.6%, respectively, and the average pore diameter decreased by 0.203 nm. Furthermore, the total acid content of PAC-SFG was 0.505, which was greater than those of the other samples. Additionally, the desorption and activation mechanisms in situ were determined under the optimum reaction conditions. The results showed that the activator gas reacted with C to form new functional groups, Lewis acid sites, and developed pore structures, which could increase Hg0 adsorption efficiency from 66% to 86% after the adsorption/desorption cycles. This study provides a novel idea for the reuse of SPAC, and this research is expected to provide valuable guidance for Hg0 removal and SPAC activated in situ during rapid desorption processes in future large-scale engineering applications.

Promoting elemental mercury immobilization performance from smelting flue gas over a wide temperature range via cobalt-doped copper sulfide adsorbents

Copper sulfide (CuS) sorbent exhibits great potential for gaseous elemental mercury (Hg0) decontamination, but it still suffers from a narrow operating temperature. Therefore, designing advanced CuS sorbents that have a high activity level for capturing Hg0 and thermal stability at a high temperature range is challenging. Herein, we propose a metal doping strategy to fabricate a bimetallic sulfide adsorbent. Benefiting the unique structure and composition, a mesoporous structure and an abundance of unsaturated sulfur sites ensure that CuxCo(1-x)Sy provides a desirable level of adsorption for Hg0. The experimental results indicate the optimum Co doping mass concentration of 5%. The Cu0.95Co0.05Sy not only performs satisfactory Hg0 adsorption at elevated temperatures (Hg0 average adsorption efficiency of over 97.3%, Hg0 average adsorption rate of over 2.7μg/g/min), but also presents an exciting regeneration and recycle performance (a Hg0 adsorption efficiency of over 94% after 10cycles). The adsorption capacity of Cu0.95Co0.05Sy at the breakthrough threshold of 25% reaches 5.22mg/g, surpassing most of metal sulfide sorbents for Hg0 immobilization at 150°C. As far as Hg0 adsorption is concerned, the composition of typical smelting flue gases has almost no effect. According to further studies, unsaturated coordination short-chain sulfur (S22-) sites are essential for adsorption of Hg0 and are capable of directly forming α-HgS from Hg0. In both the contrast experiment and density functional theory calculations, the cobalt doping strategy enhances the thermal stability of the active S22- ligand and the Hg0 adsorption properties. This study not only provide a prospective adsorbent for Hg0 sequestration at wide temperature range, but also explores a method of utilizing gaseous contaminants for resource utilization.

Integration of cadmium sulfide quantum dots with calcium alginate microbeads for dual-functional mercury (II) ion sensing and removal

Integration of cadmium sulfide quantum dots with calcium alginate microbeads for dual-functional mercury (II) ion sensing and removal

Deeply insight into the inhibition mechanism of SO2 on mercury oxidation over Mn/CNT: A DFT study

Deeply insight into the inhibition mechanism of SO2 on mercury oxidation over Mn/CNT: A DFT study

Hydrophobic hyper-cross-linked polymer shells encapsulating dispersed nanoscale CuS boosting mercury immobilization

Hydrophobic hyper-cross-linked polymer shells encapsulating dispersed nanoscale CuS boosting mercury immobilization

Fluorescent cellulose hydrogels based on corn stalk of double sulfhydryl functional group modification for Hg(II) removal and detection

Ions of mercury, one of the most hazardous heavy metals in nature, pose serious risks to the environment and human health. Blue sulfur-doped carbon dots (SCDs) from corn stalks were utilized as material. The SCDs were incorporated into a carboxylated hydrogel modified with sulfur, and a compound gel (SCDs-KTOCS gel) was successfully fabricated for simultaneous fluorescence detection and Hg(II) adsorption. This enabled the effective identification and removal of Hg(II) from contaminated water. The chemical content, fluorescence properties, and adsorption behaviors of the SCDs-KTOCS-gels were analyzed. The results demonstrate that the SCDs-KTOCS-gels exhibited effective Hg(II) adsorption (193mg/g) and an extensive linear spectrum for Hg(II) fluorescence emission (150-500mg/L; detection limit=1.5668mg/L). The adsorption values fit well with the Temkin models and pseudo-second-order kinetics. Additionally, Hg(II) detection and adsorption in the SCDs-KTOCS-gels were examined. By exchanging the existing probe for a suitable one that fits various relevant applications, this study suggests an environmentally friendly and sustainable method of producing materials for removing and detecting Hg(II) and constructing a fluorescence hydrogel for the detection and adsorption of different metals.

Experimental and DFT studies of mercury adsorption and oxidation on CuCo2O4(110) surface

Experimental and DFT studies of mercury adsorption and oxidation on CuCo2O4(110) surface

Multifunctional Ni-MOF (3D) with N-rich structures for self-generated reactive oxygen species and enhanced electron transfer for synergistic degradation of organic pollutants and removal of Hg(II)

Multifunctional Ni-MOF (3D) with N-rich structures for self-generated reactive oxygen species and enhanced electron transfer for synergistic degradation of organic pollutants and removal of Hg(II)