Removal Of Mercury Ions Research Articles

Adsorption Evaluation for the Removal of Nickel, Mercury, and Barium Ions from Single-Component and Mixtures of Aqueous Solutions by Using an Optimized Biobased Chitosan Derivative.

In this experimental study, the use of 5-hydroxymethyl-furfural (HMF) organic compound as a grafting agent to chitosan natural polymer (CS) was examined. One optimized chitosan derivative was synthesized, and then tested (CS-HMF), in order to uptake nickel, mercury, and barium metal ions from single- and triple-component (multi-component) aqueous solutions. The characterization of the material before and after the metal uptake was achieved by scanning electron microscopy (SEM). The ability of the adsorption of CS-HMF was tested at pH = 6. The adjusting of temperature from 25 to 65 °C caused the increase in the adsorption capacity. The equilibrium data were fitted to the models of Langmuir and Freundlich, while the data from kinetic experiments were fitted to pseudo-1st and pseudo-2nd order models. The best fitting was achieved for the Langmuir model (higher R2). The adsorption capacity for nickel, mercury, and barium removal at 25 °C (single component) was 147, 107, and 64 (mg/g), respectively. However, the total adsorption capacity for the multi-component was 204 mg/g. A thermodynamic study was also done, and the values of ΔG0, ΔH0, and ΔS0 were evaluated.

A composite adsorbent of ZnS nanoclusters grown in zeolite NaA synthesized from fly ash with a high mercury ion removal efficiency in solution

In this study, the nanocomposite adsorbent (ZnS-zeolite NaA) was prepared by a simple ion-exchange method, which modified the zeolite NaA synthesized from fly ash. The removal efficiency, adsorption mechanism of mercury ions by ZnS-zeolite NaA and release of zinc ion into aqueous solution during the adsorption process were determined. The results showed that ZnS nanoclusters were introduced the supercages of zeolite by ion exchange to synthesize the ZnS-zeolite NaA with high removal capacity for Hg2+ in the initial pH 2–7 of solution. Determination of the adsorption kinetics and thermodynamic parameters, in combination with X-ray diffraction, X-ray photoelectron spectroscopy and transmission electron microscopy analyses, revealed that the Hg2+ adsorption by ZnS-zeolite NaA was Hg2+ complexed and ion exchanged with ZnS in the ZnS-zeolite NaA to form stable HgS, and then, the released Zn2+ was adsorbed by the zeolite, preventing Zn2+ pollution. The Hg2+ removal rate was greater than 99.90% with the coexistence of either Zn2+ or Cu2+, Cd2+ and Pb2+. After five repetitions, the Hg2+ removal rate by the ZnS-zeolite NaA was only slightly decreased by 2%. Therefore, ZnS-zeolite NaA synthesized using fly ash has potential for broad application as a Hg2+ adsorbent.

Preparation and characterization of powdered and granular activated carbon from Palmae biomass for mercury removal

Two forms of activated carbon (i.e., granular and powdered forms) used to test mercury removal in solution. These activated carbons were obtained from the shells of a palmae biomass and used in mercury ion removal in aquatic systems. The African palmae shell taken out from a broadly and simply full-fledged palm tree. This biomass serves as a precursor in the formulation of activated carbons not documented. The powdered and granular fractions of activated carbons described for chemical composition, isoelectric point, and surface area. The mechanism of reactions and the kinetics involved were studied using the results of protonation and rate limitations. The parameters used in the batch mode study included pH, contact time, initial concentration of the adsorbate and the dose of the activated carbons. A comparison of performances, contact time demonstrated the highest adsorption efficiency of 93% for the powdered activated carbon and 92% for the granular activated carbon. The dosage recorded the lowest adsorption efficiency of 84% using granular activated carbon. Comparatively, this study brought to the fore that activated carbon derived from the Plamae biomass remains a novel bio-sorbent

Photocatalytic reduction and removal of mercury ions over mesoporous CuO/ZnO S-scheme heterojunction photocatalyst

In this contribution, a novel mesoporous CuO/ZnO heterojunctions were fabricated and designed through a wet chemical process in the presence of F127 surfactant. TEM image of mesoporous CuO/ZnO heterojunction showed a homogeneous size distribution with uniform spherical with particles size ~20 nm. The surface area of pristine ZnO NPs was estimated to be 200 m2/g, which reduced to 175 m2/g at 4% CuO/ZnO heterojunction. The synthesized CuO/ZnO heterojunctions were exhibited to effectively reduction and removal of Mercury (Hg(II)) ions through visible light. The optimized mesoporous 3% ZnO/CuO heterojunction exhibited the highest photoreduction efficiency compared to commercial P-25 and pristine ZnO NPs. The photoreduction/removal efficiency of Hg(II) over 3%CuO/ZnO heterojunction was reached up to 100% within 60 min, which is ~14 and ~24 times higher than P-25 and pristine ZnO NPs, respectively. The rate constant of mesoporous 3% ZnO/CuO heterojunction is better 30 and 54 order magnitudes than that compared with P-25 and pristine ZnO NPs, respectively. This is explained by the mesoporous CuO/ZnO heterojunctions greatly promotes the utilization light rate owing to its characteristic architecture, increases the surface area and pore volumes, promoting mass diffusion and providing more active sites, enhances the photoinduced electrons transfer the as a result of the formation of p-n types CuO/ZnO heterojunctions. Nevertheless, the photocatalysts were readily reused and recovered for five cycles without significant loss of photoreduction efficiency.

Functionalized Mesoporous Photonic Crystal Film for Ultrasensitive Visual Detection and Effective Removal of Mercury (II) Ions in Water

AbstractMercury ion (Hg2+) contamination is a worldwide serious environment problem; exploring smart sensing and adsorption materials are urgently demanded for Hg2+ monitoring and removal. Herein, a simple 1D photonic crystal to first ever feature capabilities of visually quantitative determination and effective adsorption toward Hg2+ is facilely constructed by integrating a specifically designed thiourea‐functionalized nanocopolymer layer with a mesoporous TiO2 layer. Based on strong chelation and porous structure, Hg2+ is easily adsorbed on the copolymer and triggers vertically volumetric shrinkage, resulting in highlighted wavelength blue‐shifts and color changes in a broad Hg2+ level scope. Utilizing the adsorption characteristic, Hg2+ existing in aqueous media can be effectively removed by the photonic film with a remarkable uptake capacity of 739.6 mg g−1. This portable nanolayered film exhibits full regeneration, facile recovery, desirable selectivity toward Hg2+, and shields interference from other metal ions, which enables future application for environmental determination and remediation. Furthermore, a novel nanopolymer‐based two‐regime Hg2+‐capturing mechanism is first revealed by quartz crystal microbalance with dissipation monitoring, providing valuable references for future relevant adsorption researches.

Adsorption of Hg(II) in an Aqueous Solution by Activated Carbon Prepared from Rice Husk Using KOH Activation.

With the development of industry, the discharge of wastewater containing mercury ions posed a serious threat to human health. Using biomass waste as an adsorbent to treat wastewater containing mercury ions was a better way due to its positive impacts on the environment and resource saving. In this research, activated carbon (AC) was prepared from rice husk (RH) by the KOH chemical activation method. The characterization results of scanning electron microscopy (SEM), Brunauer–Emmett–Teller (BET), Fourier transform infrared (FTIR), Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS) showed that rice husk-activated carbon (RHAC) had good pore structure and oxygen-containing functional groups. The influences of contact time, initial concentration of Hg(II), adsorbent dosage, pH, and ionic strength on mercury ion removal were investigated. The Langmuir model was most suitable for the adsorption isotherm of RHAC, and its maximum adsorption capacity for Hg(II) was 55.87 mg/g. RHAC still had a high removal capacity for Hg(II) after five regeneration cycles. RHAC had excellent removal efficiency for mercury ion wastewater. At the same time, RH could be used as a nonpolluting and outstanding characteristic adsorbent material.

Novel bimetallic nano particles for sorption of mercury (II) from drinking water: Adsorption experiment and computational studies

The current study proposes fabrication of novel manganese and copper (Mn/Cu) based bimetallic nano particles (NPs) for adsorptive removal of mercury (Hg) ions from aqueous media and examines computational models for adsorption. The Mn/Cu bimetallic NPs were characterized for Atomic Force Microscope (AFM), Energy Dispersive X-rays Spectroscopy (EDS), X-Ray Diffraction (XRD) and Dynamic Light Scattering (DLS) techniques to investigate morphology, surface elemental composition and particle size analysis. Sorption of Hg was carried out using batch experiments in triplicate and residual Hg concentration after sorption was determined using cold vapor atomic absorption spectrometer (CV-AAS). The effect of various parameters such as pH, mass of nano particles, Hg concentration and contact time were optimized. Maximum removal efficiency was 95 % with 2.89 % RSD and maximum adsorption capacity (Q max) observed was 400 mg g-1. AFM images well separated morphology and mean grain size of 450 ± 50 nm of particles, DLS measured average particles size as 110 nm while XRD pattern and EDS results showed successful adsorption of Hg on Mn/Cu bimetallic surface. Ab initio based computational models for different geometries were optimized using semi empirical method through Gaussian software. Computational molecular models were optimized for structures before and after Hg sorption and important physical parameters such as electron spin, Root mean square (RMS) gradient, Adsorption energy, Mulliken charge density (Q) and bond lengths (BL) before and after adsorption were computed. It was concluded that Langmuir adsorption isotherm was favorable for this study and interaction of Hg was more favorable with Mn than Cu because of less adsorption energy (-112.48 eV) and stronger bond formation between them having bond length of 1.6433 Å.

Green synthesis of SnO2-ZnO-eggshell nanocomposites and study of their application in removal of mercury (II) ions from aqueous solution.

Mercury (Hg) in dental amalgam is the world's hidden source of mercury contamination. The development of more eco-friendly and cost-effective adsorbents to reduce mercury pollutants in wastewater is highly desirable and is still a major challenge. In this study, a novel nanocomposite was synthesized and used as an efficient adsorbent for the removal of Hg(II) ions from aqueous solution. A green and cost-effective method was described to the synthesis of SnO2-ZnO-eggshell nanocomposites using teucrium polium extract as a renewable reductant and mild stabilizer. The biosynthesized nanocomposites were characterized by various techniques. The novel SnO2-ZnO-eggshell nanocomposites were used as an effective adsorbent in the removal of mercury (II) ions. To achieve the maximum absorption efficiency of Hg(II) ions, the effect of operating factors such as pH value, the dose of catalyst, the initial metal concentration of Hg(II) ions, and catalyst type were evaluated. The removal percentage and adsorption capacity of Hg(II) were obtained 99.15% and 396.6mg.g-1, respectively, under optimal conditions after 5 minutes. The selectivity of SnO2-ZnO-eggshell nanocomposites for the adsorption of metal ions was studied, and the highest selectivity was obtained for adsorption of Hg (II) ions. Furthermore, the SnO2- ZnO-eggshell nanocomposites could be recovered and reused at least three times without considerable loss of their efficiency. The present approach has advantages such as rapidity, simplicity, selectivity, low cost and, most importantly, the use of nanocomposites containing a bio-waste material of eggshell for removal of Hg(II) ions from aqueous solution.

Efficient removal of mercury ions with MoS2-nanosheet-decorated PVDF composite adsorption membrane.

The exploitation of a new adsorbent with a high adsorption performance and recyclability is of great practical significance for the treatment of wastewater containing mercury ions. In this study, a novel membrane adsorbent was fabricated by blending MoS2 nanosheets into a PVDF polymer matrix (P-PVDF/MoS2) followed by non-solvent-induced phase conversion. This material was able to bind mercury ions and was not affected by the solution ionic strength, co-existing anions, or interfering heavy metal ions. The optimal pH range for mercury ion elimination was 4.5-6.0, and P-PVDF/MoS2 exhibited a maximum adsorption capacity of 578mgg-1. The pseudo-second-order adsorption kinetics and Langmuir isotherm models best described the adsorption process. The adsorption mechanism was mainly monolayer chemisorption, for which the S groups were the major active sites. Furthermore, the membrane could be removed from the aqueous solution easily using tweezers, and the removal efficiency of mercury ions remained over 90% after ten cycles. This study suggests that the inexpensive and recyclable P-PVDF/MoS2 membranes can be used for the efficient removal of heavy metal ions from wastewater at a large scale.

Multiuse Al-MOF Chemosensors for Visual Detection and Removal of Mercury Ions in Water and Skin-Whitening Cosmetics

Water and cosmetics containing mercury can cause damage to the skin and body. There is a great need for in situ monitoring and removal of mercury ion concentrations with a highly selective, sensiti...

Recent Progress in Functional Materials for Selective Detection and Removal of Mercury(II) Ions

AbstractSevere disease and environmental pollution derived from heavy metal ions has become one of the major problems in global public health. In particular, mercury(II) as one type of highly poisonous pollutant can destroy human metabolism, central nervous system, and immune system, representing a critical threat to living systems. Therefore, exploitation of new strategies for designing and synthesizing eco‐friendly, efficient, and economical materials for selective detection and removal of Hg2+ is of great importance. Among the various measures for sensing, detection, and removal of mercury ions, advanced functional systems including nanomaterials, polymers, aggregation‐induced emission luminogens, and porous materials have attracted considerable attention over the past years due to their capabilities of real‐time detection, rapid removal, great anti‐interference, quick response, high selectivity, and low limit of detection. In this review, some efficient techniques and strategies for the detection and removal of mercury in aqueous solutions using the abovementioned functional materials are overviewed and the ways in which these advanced material systems are used to tackle the problem of mercury pollution are also discussed.

Removal of Mercury Ions from Aqueous Solutions by Crosslinked Chitosan-based Adsorbents: A Mini Review.

Abatement of mercury emissions in air and waters has become a global challenge due to the toxicity of mercury species for life, yet actual remediation techniques are limited. In particular, adsorption of mercury ions onto solids is widely used but most adsorption techniques are not specific, and in turn, removal efficiency is lower. Adsorbents developed so far include activated carbon, clay, bentonite, cellulose and chitosan. Chitosan derivatives have recently attracted research attention for water purification because their molecular frames contain a large amount of -NH2 and -OH groups that can chelate with metal ions specifically. This manuscript reviews recent advances in chitosan-based adsorbents designed to remove mercury ions from wastewater. Focus is placed on their design, synthesis, characterization, adsorption properties, adsorption mechanisms and applications.

Thiosemicarbazide-grafted graphene oxide as superior adsorbent for highly efficient and selective removal of mercury ions from water

In this work, the superior nanoadsorbent (GO-TSC) for highly effective adsorption of mercury ions from water solutions was developed, by grafting the thiosemicarbazide molecules (TSC) to the graphene oxide (GO) nanosheets. GO-TSC combines the extraordinary properties of GO, such as high specific surface area and an excellent dispersibility in aqueous solutions with strong affinity of TSC molecules to Hg(II) ions. The experiments show that the adsorption of Hg(II) on the GO-TSC is significant in a broad pH range, and reaches maximum value (close to 100%) at pH 3–4, with the maximum adsorption capacity of 231 mg g−1 at pH 3.5. Due to the excellent dispersibility of GO-TSC nanosheets, an extremely small GO-TSC dosage of 5 mg L-1 is required to remove Hg(II) ions from aqueous solution in a short contact time (from 10 to 30 min for adsorption of 90–95% Hg(II)). X-ray photoelectron spectroscopy indicate that the adsorption of Hg(II) is based on the chemisorption, and Hg(II) ions can be complexed by a single TSC molecule as bidentate chelating agent (S–Hg–N), or two neighboring TSC molecules (S–Hg–S). Due to the formation of strong S–Hg–N and S–Hg–S interactions, the selectivity of the GO-TSC toward Hg(II) is impressive. Hg(II) ions can be removed from aqueous solutions with very high ionic strength and high concentration of potentially coexisting ions.

Multifunctional Binding Strategy on Nonconjugated Polymer Nanoparticles for Ratiometric Detection and Effective Removal of Mercury Ions.

Developing a multifunctional platform for the selective detection and effective removal of toxic ions is a major challenge when addressing heavy metal contamination in environmental science. Herein, novel nonconjugated polymer nanoparticles (PNPs) called mercaptosuccinic acid-thiosemicarbazide PNPs (MT-PNPs) with appealing fluorescence and stability are synthesized via facile one-step hydrothermal treatment for attractive sensing and simultaneous removal of mercury(II). Interestingly, aggregation-induced fluorescence switch-off and scattering enhancement are found upon the addition of Hg2+, rendering MT-PNPs as a ratiometric sensor for selective and accurate Hg2+ monitoring. A wide linear range (0.1-1471 μM) and a low detection limit (95 nM) are obtained. This dual-signal opposite responses triggered by Hg2+ originate from the formation of MT-PNP-Hg2+ congeries via the multisite binding between S,N,O-containing groups of MT-PNPs and mercury. Meanwhile, target-induced aggregation renders an effective Hg2+ separation from contaminative aqueous media by MT-PNPs, which exhibits a satisfactory absorption efficiency of 90.42% within 50 min. Upon the simple Na2S treatment, the MT-PNPs can be regenerated and reused. This work thus delivers an applicable method for the ratiometric detection and effective removal of mercury with the novel nonconjugated PNPs, offering potential in tackling the problem of heavy metal ion pollution for environmental monitoring and remediation.

Preparation of ultra-lightweight and surface-tailored cellulose nanofibril composite cryogels derived from Date palm waste as powerful and low-cost heavy metals adsorbent to treat aqueous medium

In this study, new bio-based crogels as adsorbents were prepared from date palm tree waste (Phoenix dactylifera L). Cellulose nanofibrills (CNFs) and cellulose nanofibrills cryogels modified with 10 % GO and Fe3O4 nanoparticle as filler (CNFs/GO/Fe3O4) were prepared by facile freeze drying methodology. The unmodified and modified cryogels were characterized by fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FESEM), X-ray diffraction analysis (XRD), energy-dispersive X-ray spectroscopy (EDAX), specific surface area (BET), thermogravimetric analysis (TGA) and mechanical test. In the following, CNFs/GO/Fe3O4 cryogels were achieved with low density (0.0139 (g/cm3)), ultra-porosity (99.46 %), appropriate specific surface area (SBET = 55 (m2/g)) with more significant thermal and mechanical properties than unmodified cryogel. Furthermore, the adsorptive removal of chromium (VI), lead (II) and mercury (II) ions was investigated by response surface methodology (RSM) with central composite design (CCD), on to CNFs/GO/Fe3O4 cryogels. Optimal conditions resulting from the effective parameters such as pH, adsorbent dosage and contact time were assessed via RSM for this novel adsorbent. The adsorption kinetics were fitted well with pseudo-second-order model and the adsorption capacity of Pb(II), Hg(II) and Cr(VI) on CNFs/GO/Fe3O4 cryogels by Langmuir model concluded 126.58, 36.70 and 73.52 mg/g, respectively at 298 ±1°K. In addition, CNFs/GO/Fe3O4 cryogels could be successfully reused even after four cycles.

The biosorption of mercury by permeable pavement biofilms in stormwater attenuation

This study reports on the evaluation of the equilibrium, thermodynamics and kinetics of mercury (II) biosorption using a living biofilm, developed on a nonwoven polypropylene and polyethylene geotextile, typically used within the structure of Sustainable Drainage System (SuDS) devices. Batch biosorption assays were carried out with variables such as pH, initial concentrations, contact time, temperature and biofilm incubation time. Langmuir, Freundlich and Dubinin Radushkevich (D-R) models were applied to the equilibrium data which revealed the maximum biosorption capacities and efficiencies at pH 5.5 with a contact time of 120 min at 25 °C. With 20 mg L-1 added Hg (II), living biofilm samples with incubation times of 1, 7, 14, 21 and 28 days, biosorption values were 101.31 (55.72%), 24.41 (67.12%), 16.81 (61.37%), 9.70 (62.57%) and 13.34 (65.38%) mg g-1, respectively. Free mean biosorption energy from the D-R model was between 2.24 and 2.36 kJ mol-1 for all biofilm development incubation times, that revealed the physical biosorption mechanism for Hg(II). The thermodynamic studies showed that the Hg(II) biosorption of living biofilm was thermodynamically feasible and had a spontaneous and exothermic nature. Kinetic parameters revealed that Hg(II) biosorption onto living biofilm had a good correlation with a pseudo second-order kinetic model. FTIR spectra after biosorption suggested that amine, hydroxyl and carboxyl groups were the main functional groups available and responsible for Hg(II) biosorption onto living biofilm. Experimental data suggested that a living biofilm developed on a nonwoven polypropylene and polyethylene geotextile can be efficient in the removal of mercury ions from contaminated urban and industrial runoff.

Glutathione Modified Fluorescent CdS QDs Synthesized Using Environmentally Benign Pathway for Detection of Mercury Ions in Aqueous Phase.

An adept, rapid and novel water-soluble glutathione functionalized CdS quantum dots (GSH@CdS QDs) were fabricated using green pathway for sensing of heavy metal contamination prevalent in industrial wastewater. GSH@CdS QDs were facilely synthesized in an aqueous phase reaction and were effectively characterized using FT-IR, XRD, FESEM, HRTEM and EDX techniques. The distinct fluorescence characteristics of GSH@CdS QDs were explored and the QDs showed selective sensitivity towards mercury ions with a low limit of detection of 0.54nM under optimal conditions. The detailed interaction between GSH@CdS QDs and Hg2+ and the probable fluorescence quenching mechanism were established in this study. In comparison to already reported fluorescent probes, GSH@CdS QDs showed high sensitivity, biocompatibility, long fluorescence stability and convenient removal of mercury ions. Graphical Abstract Facile green route for the fabrication of glutathione capped CdS quantum dots for fluorescence-based detection of toxic Hg2+ ions.

Feasibility of mercury (II) ion removal by nitrated polycarbonate derived from waste optical discs

Advanced technology has led to the generation of the massive amount of electrical and electronic wastes, including compact discs and digital versatile discs. These optical discs are often ended up in landfills and incinerators, resulting in severe environmental degradation. This research aims to recover polycarbonate from waste optical discs and exploring its potential as a sorbent for the removal of mercury in water. The recovered polycarbonate was nitrated to enhance its efficiency in removing mercury (II) ion. The nitrated polycarbonate was characterized using Fourier-transform infrared spectroscopy, field emission scanning electron microscopy, thermogravimetric analysis, energy-dispersive X-ray spectroscopy and Brunauer–Emmett–Teller surface area analysis. Response surface methodology was employed to investigate the effects of agitation rate, contact time, pH, initial concentration, sorbent dosage on the mercury (II) ion removal efficiency via a central composite design. According to the quadratic model, an optimum response can be achieved at 188.6 rpm of agitation, 150 min of contact time, pH 7.55 and 1.50 mg/L of initial mercury (II) ion concentration. The adsorption process was found to follow the Freundlich isotherm model, and the adsorption mechanism was found to obey the pseudo-second-order kinetic model that indicates the chemisorption process. The results of this study showed that the nitrated PC with a maximum adsorption capacity of 0.289 mg/g has the potential to be used as a sorbent in water treatment for the removal of mercury (II) ion in water.

Adsorptive removal of mercury (II), copper (II), and lead (II) ions from aqueous solutions using glutathione-functionalized NiFe2O4/graphene oxide composite

The aim of the present study was to develop a novel adsorbent through decorating the surface of graphene oxide (GO) nanosheets with nickel ferrite (NiFe2O4) magnetic particles and subsequent functionalized with an eco-friendly and biologically active tripeptide, glutathione (GSH). Diverse characterization techniques including FE–SEM, EDX, XRD, FT–IR, VSM and BET along with the pHpzc measurements were employed to analyze the features of GSH-NiFe2O4/GO composite in detail. The efficacy of the composite for adsorption of three toxic heavy metal ions including Hg(II), Cu(II), and Pb(II) was assessed in aqueous media, individually. The effects of solution pH, operating time, initial metal ion concentration on capturing metal ions by GSH-NiFe2O4 were systematically studied in batch systems. The adsorption of metal ions was severely pH-dependent. Notably, the removal efficiencies of higher than 94% was obtained at pH 5.0 and 6.0 from 20 mg L−1 single solution containing Pb(II) and both Hg(II) and Cu(II) ions, in the respective order. The adsorption kinetics was nicely fitted by the pseudo-second-order and Elovich rate equations, whereas Freundlich isotherm equation described well the equilibrium adsorption data. The maximum adsorption capacity was found to be 272.94, 266.22, and 204.06 mg g−1 for Hg(II), Cu(II), and Pb(II) at 298 K. The experiments in binary solutions containing interfering ions clarified that prepared composite has higher selectivity toward Hg(II) than Pb(II) or Cu(II). Moreover, the Zn(II) and Fe(II) cations showed negligible competitive adsorption with all three target ions. The findings also demonstrated that GSH-NiFe2O4 has a prominent performance to decontaminate the groundwater samples spiked with the aforementioned metal ions.

One-dimensional graphene for efficient aqueous heavy metal adsorption: Rapid removal of arsenic and mercury ions by graphene oxide nanoribbons (GONRs)

There is a knowledge gap for the application of one-dimensional graphene in the adsorption process. Our hypothesis was based on the fact that graphene oxide nanoribbons (GONRs) as one-dimensional graphene with more desired edges and specific surface area than other carbonaceous nanomaterials have more oxygen containing functional groups (active sites) on their edges and basal planes and therefore are more capable in adsorption of pollutants. In this regard, we synthesized GONRs by unzipping of multi-walled carbon nanotubes (MWCNTs) and investigated the adsorption behavior of GONRs by ultrasonic-assisted adsorptive removal of As(V) and Hg(II) ions from aqueous solution. The obtained results showed that As(V) ions are more favorably adsorbed onto the GONRs than Hg(II) ions and with increasing initial As(V) and Hg(II) ions concentration to 300 ppm, the equilibrium adsorption uptake of the synthesized GONRs increases to 155.61 and 33.02 mg/g for As(V) and Hg(II) ions, respectively through a rapid separation process in just 12 min. Also, three kinetic models and Freundlich and Langmuir adsorption isotherms were applied to evaluate the obtained experimental results. Our findings highlight the potential application of GONRs as one-dimensional graphene adsorbent with more desired edges than MWCNTs and graphene oxide (GO) and high adsorption capacity for selective removal of heavy metals.