Adsorbent For Mercury Removal Research Articles

Plasma-engineered sugarcane bagasse: a novel strategy for efficient mercury removal from aqueous solutions.

Metal ion adsorption using agro-industrial residues has shown promising results in remediating contaminated waters. However, adsorbent effectiveness relies on their properties, often necessitating processing for modification. Considering this, plasma treatment is effective in modifying material surfaces physically and chemically. This study investigated the modification of sugarcane bagasse (SB) using plasma treatment and evaluated its efficacy as a novel adsorbent for mercury removal from aqueous solutions. SB underwent low-temperature plasma treatment with sulfur hexafluoride (SF6) as the working gas, varying treatment times (2, 30, and 60min), and fixed powers (80, 190, and 300 W) at 16Pa pressure. Characterization via SEM/EDS, FTIR, XPS, and pHpzc revealed significant structural changes like increased in porosity and alteration in proportion atomic. Additionally, the successful incorporation of fluorine was confirmed in all treatment conditions, while sulfur was detected in only some samples. Amongst the tested conditions, the SB treated with 300 W for 60min demonstrated the highest mercury removal efficiency, achieving an impressive 83.67% removal rate compared to untreated SB, which yielded only 57.95%. The adsorption mechanism exhibited both physical and chemical behavior, with chemisorption being the dominant process. The Freundlich model provided the best fit to the experimental data, with an R2 value of 0.97. In conclusion, plasma treatment can be a promising alternative for improving the physical and chemical characteristics of SB adsorbents, thereby improving their efficiency in removing mercury from aqueous solutions.

Hg0 chemisorption of magnetic manganese cobalt nano ferrite from simulated flue gas

Mercury (Hg) emissions from the flue gas of coal-fired power plants constituted the primary source of atmospheric mercury pollution, manifesting in three distinct forms: granular mercury, oxidized mercury, and elemental mercury. This pollution posed significant threats to the ecological environment. There was an urgent demand for a more effective and economically viable mercury removal technology. The magnetic Mn0.5Co0.5Fe2O4 nanoparticles were prepared via a rapid combustion process. Their capacities for mercury adsorption and regeneration were scrutinized through a fixed-bed experimental system. The outcomes revealed that Mn0.5Co0.5Fe2O4 nanoparticles, prepared at a calcination temperature of 400 °C with 20 ml of anhydrous ethanol, exhibited the most proficient adsorption of Hg°. Under these specific conditions, the average particle size of the Mn0.5Co0.5Fe2O4 nanoparticles was approximately 26.8 nm. These nanoparticles demonstrated a superior adsorption capacity of 9.48 μg·g−1 for Hg° at an adsorption temperature of 30 °C under a space velocity of 2.4 × 104 h−1. Elevating the permeation temperature to 70 °C resulted in an impressive adsorption capacity for Hg°, reaching 560.59 μg·g−1. The Hg-TPD (Hg-Temperature Programmed Desorption) and XPS (X-ray photoelectron spectroscopy) analyses revealed the involvement of chemisorbed oxygen (Oads), Mn3+, and Fe3+ in the adsorbent, facilitating the oxidation of Hg° and generating HgO on the adsorbent surface. Following six cycles of adsorption and desorption, the adsorption capacity of Mn0.5Co0.5Fe2O4 nanoparticles for Hg° retained 71% of the first adsorption capacity, which indicated that magnetic Mn0.5Co0.5Fe2O4 nanoparticles held great promise as an adsorbent for mercury removal.

Sulfur-rich polymers from elemental sulfur-derived polysulfide salts and bisepoxides

The obtainment of polymeric materials out of green, renewable, or sustainable building blocks is an ongoing research area. Due to its large-scale derivation as a by-product of the petroleum industry and natural abundance, elemental sulfur is a prospect to ensure the sustainable production of diverse functional polymeric materials. In the present study a simple yet efficient synthesis of sulfur-rich polymers from elemental sulfur-derived polysulfide salts and bisepoxide monomers was reported. Nucleophilic ring opening step growth polymerization of bisepoxide compounds with bifunctional sulfur derivative sodium pentasulfide (Na2S5) allowed tailorable access to novel linear copolymers with polysulfide chains in the backbone and hydroxyl groups at the side chains. Functional copolymers in the range from 14.8 kDa to 24.5 kDa molecular weights (Mn) were obtained with relatively high monomer conversions (69–91 %). By simple alteration of employed bisepoxide monomers, structurally diverse copolymers were obtained. The polymerizations were efficiently conducted at ambient temperature without the need of any catalyst. Obtained copolymers incorporated alternating hydroxyl functionalities at polymer side chains which were employed as reactive handles for post-polymerization modification. By employing a multifunctional epoxide crosslinker, chemically crosslinked polymers were also fabricated. These crosslinked polymers were shown to be utilized as adsorbents for mercury removal from water. The obtained results in this study demonstrated that the proposed methodology can be employed to synthesize and fabricate structurally diverse sulfur-rich polymers that might find potential use in various material applications.

Economic evaluation of mercury removal from flue gas by recyclable CuCl2 modified magnetospheres catalyst for 1000 MW coal-fired power plant

Economic sustainability is one of the main factors restricting development of mercury pollution control technology in the flue gas. Renewable magnetospheres separated from fly ash can be used as adsorbent for mercury removal from coal-fired flue gas. Based on the actual working condition of the 1000 WM coal-fired unit, this paper analyzes the impact of magnetosphere and mercury recovery technology on the economic benefits of this technology. The results show that the recovery of magnetospheres and mercury can obtain higher economic returns. This not only can realize the deduction of operating costs, but also has certain economic investment potential. When the magnetic separation rate is greater than 6% and the selling price of the magnetosphere is greater than 720 CNY/t, the revenue of the magnetosphere recovery system can offset the operating cost of whole system. The internal rate of return of the system can reach 50% at most. When the selling price of mercury selenide is lower than 450 CNY/g, the single mercury recovery income is insufficient to offset the mercury removal cost. Within the selling price range of 450–500 CNY/g mercury selenide, the system can generate revenue, and the product qualification rate directly affects the profit and loss of the system. The coupling of magnetospheres and mercury recovery systems can make economic and technical parameters more moderate. When the selling price of magnetospheres is higher than 600 CNY/t, the magnetic separation rate is higher than 6%, and the selling price of mercury selenide is higher than 350 CNY/g, the internal return of the system will fluctuate within 13%∼120%, and the static investment recovery period will remain within 6 years. Overall, this study can provide economic guidance for mercury removal technology with renewable magnetospheres and provide data support for further commercialization of technology.

Chemical modification of polystyrene foam using functionalized chitosan with dithiocarbamate as an adsorbent for mercury removal from aqueous solutions

Chemical modification of polystyrene foam using functionalized chitosan with dithiocarbamate as an adsorbent for mercury removal from aqueous solutions

Engineering linkage as functional moiety into irreversible thiourea-linked covalent organic framework for ultrafast adsorption of Hg(II)

Development of novel functionalized covalent organic frameworks (COFs) as adsorbent for removal of mercury from environment is of great significance, but the conventional strategies for functionalizing COFs always sacrifice porous properties and suppress the exposure of functional sites, which goes against the rapid adsorption of Hg(II). Here, we show the rational design and preparation of the first thiourea-linked COFs via engineering the COFs linkage as functional moiety for ultrafast and selective adsorption of Hg(II). Two thiourea-linked COFs JNU-3 and JNU-4 were prepared via tautomerism reaction of 1,3,5-triformylphloroglucinol with 1,4-phenylenebis(thiourea) and 1,4-biphenylenebis(thiourea), respectively. The thiourea serves as not only linkage to connect the building block into irreversible crystalline structure, but also functional moiety to give no occupation of the COF pore and full exposure to Hg(II) with strong affinity, offering the JNU-3 and JNU-4 large adsorption capacity (960 and 561 mg g−1, respectively) and ultrafast kinetics (equilibrium time of 10 s) for Hg(II). The proposed strategy for the design of functional COFs with inherent linkage as functional moiety largely promotes the performance of COFs for diverse applications.

Experimental Study on the Mercury Removal of a H2S-Modified Fe2O3 Adsorbent

Owing to the massive mercury emission from coal-fired power plants and other nonpower industries worldwide, it is imperative to develop non-carbon-based adsorbents for mercury removal. In this work...

Ion exchange resin derived magnetic activated carbon as recyclable and regenerable adsorbent for removal of mercury from flue gases

Regenerable ion exchange resin derived magnetic activated carbon (Fe/AC) was prepared to remove mercury from flue gases at 120–180 °C under a high space velocity of 240000 h−1, in this study. The Fe/AC showed higher mercury removal efficiency than those of either magnetic activated carbon without activation or commercial coconut-activated carbon. The optimum temperature for removal of mercury from flue gases was determined to be 120 °C and the existence of SO2 in flue gases promoted the mercury removal efficiency of Fe/AC. Mercury compounds of HgS (metacinnabar), HgO, HgS (cinnabar) and HgSO4 were found over spent adsorbents. The HgO was generated through the reaction of mercury with lattice oxygen and chemisorbed oxygen, while the formation of HgS was due to the reaction between mercury, FeS and sulfur over the adsorbent. The lattice oxygen could oxidize SO2 to SO3, which further reacted with mercury to form HgSO4. The Fe/AC presented excellent regeneration and reuse ability, the mercury removal efficiency of which showed a great increase even after 5 runs of regeneration. The crystalline structure of Fe/AC changed remarkably after regeneration and the FeS over Fe/AC was converted to Fe3O4. The above excellent properties suggest that Fe/AC might be a promising adsorbent to remove mercury from flue gases.

A water-stable functionalized NiCo-LDH/MOF nanocomposite: green synthesis, characterization, and its environmental application for heavy metals adsorption

Removal of toxic heavy metals from aquatic environments has become a major concern due to environmental problems and the potential hazards and risks posed by them. Nowadays, the adsorption method as one of the most effective methods of removing pollutants has attracted increasing attention among chemists and environmental researchers. However, one of the challenges is to design and develop more effective adsorbents as well as to prepare them via greener and safer approaches. In line with these goals, a functionalized Ni50Co50-layered double hydroxide/UiO-66-(Zr)-(COOH)2 nanocomposite (LDH/MOF NC) was prepared via a facile and “green“ synthesis protocol and used as an effective adsorbent for removal of mercury and nickel cations from aqueous media. UiO-66-(Zr)-(COOH)2 nanoparticles were in situ grown homogeneously over the surface of the functionalized two-dimensional ultrathin Ni50Co50-LDH sheets. A green organic-solvent-free route was used to prepare the LDH/MOF NC in which the water is used as a green solvent. The adsorption performance of LDH/MOF NC for removal of Hg(II) and Ni(II) cations was studied and the influence of some experimental factors, such as solution pH, initial metal concentration, and contact time, on the adsorption process were investigated. The theoretical maximum adsorption capacities based on the Langmuir isotherm were found to be 509.8 mg g−1 and 441.0 mg g−1 for Hg(II) and Ni(II), respectively, under constant conditions. We believe that the facile and “green” synthesis method used in this work can be a starting point for the fabrication and development of similar composite materials for future works, especially for use in adsorption, extraction, catalysis, and drug delivery applications.

Synthesis of a new thiophenol-thiophene polymer for the removal of mercury from wastewater and liquid hydrocarbons

This work reports the synthesis of a novel thiophenol-thiophene polymer (termed KFUPM-Hg) and its suitability as an adsorbent for mercury removal from wastewater and liquid hydrocarbons. KFUPM-Hg was synthesized through a Friedel-Crafts polycondensation reaction of thiophenol and thiophene in the presence of p-formaldehyde as a linker. The crosslinked polymer structure was characterized using solid-state 13C-nuclear magnetic resonance (NMR) and Fourier-transform infrared spectroscopy (FTIR). Thermogravimetric analysis was performed to assess the polymer thermal stability, which indicated that the polymer is thermally stable to over 300 °C. A series of batch adsorption studies were used to investigate the effects of different parameters (pH, temperature, concentration, and time) on the mercury removal from aqueous solution as well as from a model liquid hydrocarbon media (decane/toluene mixture). The batch adsorption studies in aqueous media showed near quantitative removal of inorganic mercury (II) at 100 ppm using the thiophenol-thiophene polymer adsorbent. Furthermore, the thiophenol-thiophene polymer demonstrated excellent removal capabilities of methylmercury in a decane/toluene hydrocarbon mixture. Mercury adsorption onto KFUPM-Hg is an exothermic reversible physical process and follows pseudo-second order adsorption kinetics. Remarkably, these removal capabilities were achieved using polymers that directly incorporated thiophenol and thiophene groups during synthesis without the use of thiol-ene post-synthesis modifications.

Adsorption of mercury species on selected CuS surfaces and the effects of HCl

Abstract Mercury removal is a hot topic in environments. The present work investigated the adsorption of Hg species on the surfaces of CuS, which performs excellently in experiments as adsorbents for mercury removal, with the dispersion corrected density functional theory. In this work, a pair of asymmetric surfaces (marked as slab1 and slab2) formed by breaking the weakest bond along (001) direction are chosen to present CuS surfaces. It is found that the HCl modification to the CuS may lead to the isolated Cl atoms and defects in the CuS surface. Hg atom can be adsorbed on the perfect CuS surface weakly. The surface defects and the isolated Cl atoms could strengthen the bonding of the Hg species to the surfaces. However, the mechanisms for the defects and Cl affect the mercury adsorption ability in slab1 and slab2 are quite different. The adsorption of HgCl and HgCl2 is much stronger than the adsorption of Hg, indicating that Hg would be first be released, rather than Cl, from the adsorbent during the desorption process.

Nano-bentonite as a low-cost adsorbent for removal of mercury from aqueous solution

Study of the adoptive of mercury removal (Hg II) from aqueous solution was investigated by low-cost nanoparticle bentonite. Nanoparticle bentonite was prepared by the heating method at a temperature of 400 °C. The activation was carried out by immersed of natural bentonite in sodium hydroxide. The resulting powder was heating in the present of nitrogen gas as an activator agent. The bentonite sample was characterized by means of Scanning Electron Microscopy (SEM) and Brunai Emmet Teller (BET). The prepared bentonite had a heterogeneous surface with a particle size of 100-300 nm. The nano-bentonite was then tested in the absorption of Hg2+ synthetic were varied of the initial concentration (Co) from 5 to 400 ppm with 0.2 gram absorbent and 100 ml solution. The Hg2+ absorption amount was analysed using Atomic Absorption Spectroscopy (AAS). The adsorption capacities were fully fit with Freundlich isotherm models. It was found that the adsorption process followed the Freundlich isotherm model with n value of 1.9577 and Kf of 8.3985. Therefore, using the low-cost nano-bentonite is a potential adsorbent for removal of mercury from water solution.

Silver/quartz nanocomposite as an adsorbent for removal of mercury (II) ions from aqueous solutions

Silver nanoparticles (AgNPs) and silver/quartz nanocomposite (Ag/Q)NPs)) were synthesized by sol-gel method using table sugar as chelating agent. The synthesized nanosized materials were used for mercury ions adsorption from aqueous solutions. The materials were characterized by X-ray diffraction (XRD), Transmission Electron microscope (TEM), and surface area (BET). Adsorption of Hg2+ (10 mg/l) is strongly dependent on time, initial metal concentration, dose of adsorbent and pH value. Silver/quartz nanocomposite ((Ag/Q)NPs)) shows better efficiency than individual silver nanoparticles (AgNPs). This composite removed mercury ions from the aqueous solution with efficiency of 96% at 60 min with 0.5g adsorbent dosage at pH 6. The adsorption process explained well by the pseudo-second-order kinetic model. In conclusion silver/quartz nanocomposite (Ag/Q)NPs)) shows higher removal efficiency for mercury ions from aqueous solutions than individual silver naoparticles (AgNPs) or quartz (Q).

Fabrication of novel magnetic graphene oxide nanocomposites for selective adsorption of mercury from aqueous solutions.

In this work, a novel functionalized graphene oxide (GO) was used as an effective and selective adsorbent for removal of mercury (Hg2+). The magnetic nanocomposite adsorbent (MNA) based on GO was prepared through surface reversible addition-fragmentation chain transfer copolymerization of acrylic monomers and then the formation of Fe3O4 nanoparticles. The structure of MNAs was characterized by using FTIR, SEM, TEM, VSM, XRD, and nitrogen adsorption/desorption isotherms. The results of ion adsorption of MNAs demonstrated high selectivity and adsorption efficiency for Hg2+ in the presence of competing ions. Furthermore, the removal of Hg2+ obeyed a pseudo-second-order model and fitted well to the Langmuir isotherm model with the maximum Hg2+ uptake of 389 mg g-1. The MNA was also confirmed as good materials for re-use and maintained 86% of its initial adsorption capacity for mercury after the fifth regeneration cycles. Finally, the experimental results demonstrated that the solution pH, ion concentration, and temperature had a major impact on Hg(II) adsorption capacity. The results indicate that the MNAs with high adsorption abilities could be very promising adsorbents for the selective recovery of ions in wastewater treatment process. Graphical abstract.

$$\hbox {SnO}_{x}$$ SnO x -Impregnated Clinoptilolite for Efficient Mercury Removal from Liquid Hydrocarbon

The present study investigates $$\hbox {SnO}_{x}$$ -impregnated clinoptilolite, which is zeolite belonging to the heulandite family, for developing efficient adsorbent for mercury removal from liquid hydrocarbon. Adsorption experiments were carried out in batch method, and the effects of adsorbent dosage and contact time on the adsorption properties of mercury were investigated. We demonstrated that the $$\hbox {SnO}_{x}$$ -impregnated clinoptilolite removed the mercury from liquid hydrocarbon with high efficiency, where the maximum capacity was 0.93 ng/g, higher compared with the natural clinoptilolite (0.43 ng/g). Structure and morphology analysis also showed that $$\hbox {SnO}_{x}$$ was coated on the surface of clinoptilolite, resulting in rougher surface and smaller pore size and volume than those of natural clinoptilolite. Speciation of mercury indicated that the most removed species was organomercury (67.3%), and its removal efficiency increased with the adsorbent dosage. The isotherm analysis revealed that adsorption mechanism was governed by pseudo-second-order kinetics, indicating that the adsorption was a chemical adsorption process due to electrostatic attractions. This finding suggested that clinoptilolite/ $$\hbox {SnO}_{x}$$ was promising adsorbents for organomercury removal from liquid hydrocarbon.

Bis-phosphonated carbon nanotubes: One pot synthesis and their application as efficient adsorbent of mercury

ABSTRACTEffective, one-pot method of CNTs phosphonylation is presented. Cheap and readily available reagents are used, so the process can be easily transferred to large-scale production. The product was analyzed using spectroscopic methods (FTIR, UV-vis, XPS). Thermal properties of the bis-phosphonated nanotubes are reported for the first time. Newly obtained material was tested as an adsorbent for mercury removal from water. The sorption capacity for newly developed adsorbent was as high as 223.7 mg/g. The adsorption kinetics were studied within framework of Lagergren model, and Langmuir and Freundlich isotherms have been described. The effect of pH on the adsorption process has been evaluated and the optimal environmental conditions were determined to be neutral. The presence of bivalent ions Cd2+, Ni2+ in the solution did not affect adsorption efficiency of novel materials.

Kinetics, isotherms, and thermodynamic studies on the adsorption of mercury (ii) ion from aqueous solution using modified palm oil fuel ash

Palm oil fuel ash (POFA) is a waste material generated from the boiler due to the burning of palm oil biomass e.g. kernel shell and fiber as fuel to generate electricity. The present research focused on the study of adsorption isotherms, kinetics and thermodynamic properties on the removal of mercury (II) ion onto POFA. The prepared POFA was characterized by FTIR, TGA and BET analysis. The equilibrium data at various concentrations were analyzed by Langmuir and Freundlich isotherms models. From this present study, the maximum adsorption capacity obtained from the Freundlich isotherm was 0.99 mg/g. A kinetic study was carried out with pseudo first order and pseudo second order reaction equations. It was found that the mercury (II) ion uptake process followed the pseudo second order rate expression. Thermodynamic parameters of the Gibbs free energy (ΔG°), enthalpy (ΔH°), and entropy (ΔS°) were also determined. The negative Gibbs free energy change (-788.90 kJ/mol) and the positive enthalpy change (73,680.33 kJ/mol) indicated that adsorption was spontaneous process and endothermic nature. Overall, POFA looks to be a promising adsorbent for removal of mercury (II) ion from aqueous solutions due to its high performance and availability at low cost.

Application of a novel magnetic carbon nanotube adsorbent for removal of mercury from aqueous solutions.

In this research, multiwall carbon nanotube was magnetized and subsequently functionalized by thiosemicarbazide. After characterization by FTIR, BET, SEM, EDAX, and VSM techniques, the magnetized adsorbent (multi-walled carbon nanotubes (MWCNTs)/Fe3O4) was used for removal of Hg2+ from aqueous solutions and the experimental conditions were optimized. The adsorption capacity of 172.83mgg-1 was obtained at 25°C and pH=3 which was superior to the value obtained for initial multiwall carbon nanotube, magnetized sample, and many previously reported values. In the presence of Pb+2 and Cd+2, the adsorbent was selective towards mercury when their concentration was respectively below 50 and 100mgL-1. The adsorption process was kinetically fast and the equilibration was attained within 60min with 69.5% of the capacity obtained within 10min. The used adsorbent was regenerated by HNO3 solution, and the regenerated adsorbent retained 92% of its initial capacity. The magnetic sensitivity of the adsorbent allowed the simple separation of the used adsorbent from the solution by implying an appropriate external magnetic field. The adsorption data was well fitted to the Langmuir isotherm model, indicating homogeneous and monolayer adsorption of mercury by the adsorbent.

Adsorption Characteristics of Impregnated Adsorbent for Mercury Removal

Significant amounts of fluorescent light have been discarded every year. Mercury is released into the atmosphere in the recycling process of it, if improperly treated. The adsorption method is used to remove mercury discharged from the recycling step of fluorescent light.We studied the impregnation condition of adsorbent made from sewage sludge. And also adsorption characteristics of mercury were evaluated by impregnated adsorbent.According to our results, the adsorption efficiency of mercury was increased by impregnating adsorbent with chlorine and iodine. The adsorption capacity was described by Langmuir isotherm model.

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