Efficient Nanoadsorbent Research Articles

Dendritic fibrous nanosilica functionalized by dithiocarbamate as a highly efficient adsorbent for the removal of malachite green from waste water based on electrostatic interaction

In this work, dithiocarbamate (-NH-CS2)-functionalized dendritic fibrous nanosilica (KCC-1) with significant adsorbtion capacity was effectively synthesized using the reliable reaction process. Field emission scanning electron microscopy, FT-IR and transmission electron microscopy were used to analyze particle size and morphology of nanoadsorbent. Additionally, the functionalization of bare materials (dendritic fibrous nanosilica) with dithiocarbamate was confirmed with FT-IR and energy-dispersive X-ray spectroscopy. Furthermore, nitrogen adsorption/desorption analysis (BET equation) was utilized to evaluate KCC-1-NH-CS2 porosity (surface are, pore size, pore volume). The UV–Vis spectrophotometric method was used to evaluate organic dye removal from aqueous solutions. It was found that dithiocarbamate-functionalized KCC-1-NH2 with narrow size distribution, high surface area (133 m2/g) and effortlessly available pores had good potential for highly efficient removal of malachite green (MG) from contaminated waters. Electrostatic interactions between the negatively charged dithiocarbamate group (NH-CS2−) of nanoadsorbent and cationic MG in KCC-1-NH-CS2 channels provided a rapid (45 min) removal of this organic contaminated agent from waste water with adsorbtion capacity higher than 98%. Finally, an efficient nanoadsorbent was introduced to remove organic dyes from wastewaters and industrial purification.

Covalent modification of reduced graphene oxide with piperazine as a novel nanoadsorbent for removal of H2S gas

In the present research, piperazine grafted-reduced graphene oxide RGO-N-(piperazine) was synthesized through a three-step reaction and employed as a highly efficient nanoadsorbent for H2S gas removal. Temperature optimization within the range of 30–90 °C was set which significantly improved the adsorption capacity of the nanoadsorbent. The operational conditions including the initial concentration of H2S (60,000 ppm) with CH4 (15 vol%), H2O (10 vol%), O2 (3 vol%) and the rest by helium gas and gas hour space velocity (GHSV) 4000–6000 h−1 were examined on adsorption capacity. The results of the removal of H2S after 180 min by RGO-N-(piperazine), reduced graphene oxide (RGO), and graphene oxide (GO) were reported as 99.71, 99.18, and 99.38, respectively. Also, the output concentration of H2S after 180 min by RGO-N-(piperazine), RGO, and GO was found to be 170, 488, and 369 ppm, respectively. Both chemisorption and physisorption are suggested as mechanism in which the chemisorption is based on an acid–base reaction between H2S and amine, epoxy, hydroxyl functional groups on the surface of RGO-N-(piperazine), GO, and RGO. The piperazine augmentation of removal percentage can be attributed to the presence of amine functional groups in the case of RGO-N-(piperazine) versus RGO and GO. Finally, analyses of the equilibrium models used to describe the experimental data showed that the three-parameter isotherm equations Toth and Sips provided slightly better fits compared to the three-parameter isotherms.

Synthesis of CaO/Fe2O3 nanocomposite as an efficient nanoadsorbent for the treatment of wastewater containing Cr (III)

ABSTRACT In this study, CaO/Fe2O3 nanocomposite was studied as an efficient and novel adsorbent for the sorption of chromium (III) from aqueous media. Different analyses including FTIR, XRD, TGA-DTG, SEM/EDAX, and TEM were used to study the characteristics of CaO/Fe2O3 nanocomposite. The highest sorption efficiency using CaO/Fe2O3 nanocomposite was achieved 97.53%, which showed a high removal efficiency of Cr (III). The maximum adsorption capacity of CaO/Fe2O3 nanocomposite using Langmuir isotherm model was obtained 60.60 mg/g. Also, the adsorption data were best fitted to the pseudo-second-order kinetic model and Langmuir isotherm model. Moreover, the adsorption process was spontaneous and exothermic nature.

Sorption and separation performance of certain natural radionuclides of environmental interest using silica/olive pomace nanocomposites

This study is concerned with the sorption behavior of natural radionuclides (226Ra, 210Po, 228Th—originated from TENORM waste associated with petroleum industry) onto silica/olive pomace nanocomposite. Initially, nanocomposites of extracted silica and olive pomace are prepared and characterized by physicochemical techniques. In the batch technique, 60% SiO2 40% olive pomace (AM3) nanocomposite showed a considerable group sorption for 226Ra and 210Po larger than 228Th in 1M HNO3 and HClO4 solutions. In case of sorption by the compacted disc, sorption of 226Ra was similar to batch method, sorption of 228Th increased slightly to ~ 17%, while sorption of 210Po was decreased to 77%. Thus, AM3 nanocomposite can be considered as an efficient nano-adsorbent for sorption and separation of Ra-isotopes and 210Po-radionuclides from 226Ra–210Po–228Th admixture associated with nuclear and non-nuclear industries.

Green Synthesis of Cost-Effective and Efficient Nanoadsorbents Based On Zero and Two Dimensional Nanomaterials for Zn2+ and Cr3+ Removal from Aqueous Solutions

Novel, efficient and cost-effective heavy metals nanoadsorbents were developed. Polyaniline nanofibers were prepared at ambient conditions and their nanocomposites based on zero and two dimensional nanomaterials were developed. Polyaniline nanofibers chains were polymerized on the surface of clay layers and silica nanoparticles originated from rice husk individually using facile synthesis approach. Polyaniline nanofibers and their nanocomposites were used as efficient adsorbents for removal of Zn2+ and Cr3+ ions. The developed nanocomposites achieved superior adsorption uptake efficiency for removal of Zn2+ and Cr3+ ions compared to polyaniline nanofibers alone. The new adsorbents achieved excellent uptake efficiency for removal of Zn2+ and Cr3+ of 95 and 92% respectively. Effect of nanomaterial shape on the adsorption efficiency of metal ions was investigated. Also, effect of adsorbent dose, initial metal ions concentrations, pH of solution and contact time on the adsorption efficiency of Zn2+ and Cr3+ were investigated and tuned. Additionally, the adsorption of Zn2+ and Cr3+ ions on the nanocomposites were further analyzed using Langmuir and Freundlich models and the adsorption isotherms of Zn2+ and Cr3+ were found to be fit well with Langmuir model. This study presents a new approach for development of cost-effective and efficient adsorbents from abundance precursors for removal of heavy metal ions from industrial wastewater.

Adsorptive Removal of Recalcitrant Auramine-O Dye by Sodium Dodecyl Sulfate Functionalized Magnetite Nanoparticles: Isotherm, Kinetics, and Fixed-Bed Column Studies

Presently, the treatment of dye-polluted water is a challenging task worldwide. In this study, the adsorptive removal of Auramine-O (AO) dye by magnetite nanoparticles (MNs) and sodium dodecyl sulfate (SDS) functionalized MNs (SFMNs) were investigated. FESEM, HRTEM, EDX, and XRD were employed to characterize the MNs. In batch optimization, dye removal efficiency of 74% was obtained at contact time (40[Formula: see text]min), pH 6.5, sorbent dosage (20[Formula: see text]mg), and initial dye concentration (20[Formula: see text]mg/L). The maximum adsorption capacity of 55.56[Formula: see text]mg/g was estimated from Langmuir model and the isotherm data were fitted with Freundlich model ([Formula: see text]) for SFMNs. Pseudo-second-order kinetics was followed by both MNs and SFMNs for the adsorption of AO dye. The continuous AO dye adsorption was studied in fixed-bed column and the effects of bed height, influent flow rate, and initial dye concentration were investigated. The column performance was evaluated by breakthrough kinetic modeling and Yoon–Nelson model was fitted with the data. The results of this study showed that the surface modification of MNs using SDS enhanced the AO dye removal efficiency and SFMNs can be employed as an efficient nanoadsorbent for AO dye removal in batch and continuous mode of operation.

Adsorption of Sr(II) cations onto phosphated mesoporous titanium dioxide: Mechanism, isotherm and kinetics studies

In this work, phosphate-modified titanium dioxide nanoparticles with mesoporous structure were synthesized and utilised as an efficient nanoadsorbent for Sr(II) removal from aqueous environment. The globular titania particles with a 3–4 nm diameter with chemosorbed on their surfaces phosphate groups = Ti(O2POOH) have been obtained by liquid-phase synthesis. The characterization of titania nanoparticles were performed using XRD, TEM, IR-spectroscopy and Brunauer-Emmett-Teller analyses. The synthesized modified adsorbents exhibited SBET = 396–410 m2 g−1 and mesopore volume of 0.262 – 0.275сm3 g−1. The isotherm and kinetic models were used for the description of Sr(II) adsorption. The sample 4P-TiO2 showed the best adsorption ability for strontium ions removal. The adsorption capacity of Sr(II) onto modified 2P-TiO2, 4P-TiO2 and 8P-TiO2 samples was found to be 94.1, 172.5, 128.9 mg/g, respectively. An adsorption mechanism for Sr(II) removal was proposed. The adsorption/desorption studies were conducted to find the reusability of phosphated adsorbents. A titanium dioxide-based mesoporous material possesses a significant adsorption activity due to high content of surface acid sites. All the outcomes revealed that the phosphate modified titania showed great potential in Sr(II) removal from aqueous environment and nuclear effluents.

In-situ functionalization of GO sheets with AlOOH-FeOOH composite nanorods: An eco-friendly nanoadsorbent for removal of toxic arsenate ions from water

Water contaminated with arsenic (As) has become a worldwide problem due to its obligatory toxicity. Therefore, there is a great challenge for researchers to develop a cost-effective and highly efficient nanoadsorbent material for As removal. In this work, we have synthesized boehmite-lepidocrocite (AlOOH-FeOOH) composite nanorods mounted onto previously prepared graphene oxide (GO) surface (GO/AlOOH-FeOOH) by one step hydrothermal method. Then the prepared GO/AlOOH-FeOOH nanocomposite was sintered at 400 °C to form GO/Al2O3-Fe2O3 nanocomposite. Both the obtained GO functionalized nanocomposites were used as adsorbents for As(V) removal from water. The XRD, HRTEM confirmed the formation of γ (AlOOH-FeOOH) and γ (Al2O3-Fe2O3). TEM images revealed the formation of rod shape composite nanomaterials on GO surface. The GO/Al2O3-Fe2O3 showed magnetic properties with saturation magnetization value of 5.8emug−1. Among the two prepared nanoadsorbents the GO/AlOOH-FeOOH shows better adsorption properties with maximum uptake capacity of 24.6 mgg-1. The kinetics and isotherm experiments suggested that the adsorption process obeyed pseudo second order kinetic and Freundlich isotherm model. The presence of common coexisting anions including Cl-, SO42-, NO3- showed no significant effect on adsorption except PO43-. The mechanism of As(V) adsorption on GO/AlOOH-FeOOH includes electrostatic interaction and surface complexation reaction.

Hierarchical polydopamine coated cellulose nanocrystal microstructures as efficient nanoadsorbents for removal of Cr(VI) ions

Cellulose nanocrystals (CNCs) have been extensively explored as adsorbents for removal of heavy metals, dyes and other pollutants, but the pristine CNCs only show very limited adsorption capacity for Cr(VI) and usually demand complicated surface modification strategies to achieve acceptable Cr(VI) adsorption performance. In this work, we report a facile and efficient strategy to develop CNC-based nanoadsorbents with excellent Cr(VI) adsorption performance through polydopamine (PDA) surface modification. By controlling dopamine polymerization on the surfaces of CNCs and in the bulk solution, we achieved a hierarchical PDA coated cellulose nanocrystal (CNC@PDA) microstructure wherein PDA nanoparticles of less than 30 nm are uniformly attached on PDA coated CNCs. This special hierarchical microstructure endows the developed CNC@PDA adsorbents with a high specific surface area 101.88 m2/g thereby affording high Cr(VI) adsorption capacity 205 mg/g, which outperformed most adsorbents based on cellulose materials. Moreover, the Cr(VI) adsorbed CNC@PDA nanoadsorbents precipitate out from the solution and thus can be easily removed to reclaim the purified water. This mussel-inspired strategy to fabricate hybrid nanomaterials with hierarchical microstructures might open up new opportunity to modify cellulose-based agriculture by-products for their application in sewage treatment.

Central composite design for optimization of removal of trace amounts of toxic heavy metal ions from aqueous solution using magnetic Fe3O4 functionalized by guanidine acetic acid as an efficient nano-adsorbent

In this study, a novel and effective preconcentration and removal technique based on the use of magnetic Fe3O4 functionalized by guanidine acetic acid (Fe3O4@GAA) as a nano-adsorbent were introduced. The application of synthesized nano-adsorbent was investigated for the adsorption and removal of a trace amount of some heavy metals, such as Hg (II), Zn (II), Cu (II) and Ag (I), from aqueous samples. The synthesized nano-adsorbents were analyzed by scanning electron microscopy (SEM), Fourier transforms infrared spectroscopy (FT-IR) and X-ray powder diffraction (XRD). The diameter of the magnetic nano-adsorbents was in the range of 20–30 nm. In order to obtain maximum removal efficiency, the effects of effective parameters were optimized using a central composite chemometric design. The optimum conditions were pH of 7, nano-adsorbent amount of 14 mg and contact time of 10 min. The Fe3O4@GAA nano-adsorbent could be simply separated from the solution with the assistance of an external magnetic field, eluted with proper eluent and reused for twenty runs without a significant loss of its adsorbent activity. The adsorption efficiencies and preconcentration factors of developed procedure for target ions were in the range of 95–100% and 112–125, respectively, under the optimum condition. The obtained results revealed that the Fe3O4@GAA nano-adsorbent could be applied as a novel, simple, highly effective, reusable and cost-consuming material for the preconcentration and removal of the target toxic heavy metal ions from the aqueous solution.

Synthesis and Characterization of γ-CD-Modified TiO2 Nanoparticles and Its Adsorption Performance for Different Types of Organic Dyes

In this work, γ-cyclodextrin-modified titanium dioxide nanoparticles (NPs) as an efficient nanoadsorbent were synthesized and used to remove methylene blue (MB), malachite green (MG), crystal viole...

Possible use of synthesized nano silica functionalized by Prussian blue as sorbent for removal of certain radionuclides from liquid radioactive waste

The Prussian blue functionalized SiO2 (nano-material of SiO2-Fe-CN) was successfully prepared using a novel and simple preparation route. The SiO2 nanoparticles were functionalized by amino group by refluxing with (3-Aminopropyl) trimethoxysilane, iron (III) immobilized the modified nanoparticles through interaction with the amino group, finally, SiO2-Fe-CN nanomaterial produced as a result of potassium ferrocyanide addition. SEM, FTIR and XRD techniques were used for detecting the morphology, particle size, different functional groups and the crystal structure of the prepared nano-materials. The sorption potential of nano-material of SiO2-Fe-CN towards cationic and anionic radioisotopes from aqueous and HNO3 solutions were tested using carrier free method. The experimental results showed that nano-material of SiO2-Fe-CN have high effective retention and recovery for 134Cs, 60Co and 99Mo from nuclear liquid waste. Moreover, sorption of 90Sr/90Y is insignificant using SiO2-Fe-CN nano adsorbent material. It is a promising and efficient nano adsorbent that could be used for upscaling design and application on liquid radioactive waste treatment facility.

A natural kaolin/γ-Fe2O3 composite as an efficient nano-adsorbent for removal of phenol from aqueous solutions

Phenol and its derivatives are among the most important environmental pollutants in wastewaters. Consequently, removal of these pollutants from wastewaters using non-toxic materials and eco-friendly technologies has been of considerable interests. In this study, a composite of natural kaolin and γ-Fe2O3 nanoparticles was made via a facile co-precipitation method. The employed characterization techniques showed that the synthesized composite consisted of halloysite nanotubes that were partially covered with γ-Fe2O3 nanoparticles. Further investigations revealed that the composite has a mesoporous structure with a BET surface area of 28 m2 g−1 that results in efficient removal of phenol from aqueous solutions. The effect of different experimental parameters (such as solution temperature, solution pH, contact time, and initial phenol concentration) on the performance of the composite toward the removal of phenol was then investigated. The results demonstrated that the removal of 30 mg L−1 phenol from an aqueous solution containing 20 g L−1 of the composite is achieved after 4 h. The experimental data correlated well with the Freundlich isotherm model and suggested that the removal of phenol from aqueous solution follows the pseudo-first-order kinetics.

Hydrothermally Synthesized Co3O4, α-Fe2O3, and CoFe2O4 Nanostructures: Efficient Nano-adsorbents for the Removal of Orange G Textile Dye from Aqueous Media

We herein report the preparation of Co3O4, α-Fe2O3, and CoFe2O4 nanostructures through a hydrothermal method followed by a subsequent heat treatment. The as-prepared nanostructures exhibited good adsorption properties for the removal of Orange G (OG) textile dye. Various parameters influencing the adsorption process have been investigated such as contact time, initial dye concentration, ionic strength, adsorbent dose, and temperature. The maximum adsorption capacity values were found to be 33.3, 53.2, and 62.0 mg/g, for Co3O4, CoFe2O4, and α-Fe2O3 nano-adsorbents, respectively. The adsorption data fit the pseudo-second-order kinetic and Langmuir isotherm models well. Based on the calculated thermodynamic constants: ΔH° (3.660, 14.82, and 0.4710 kJ/mol), ΔG° (from −0.8090 to −1.109, from −0.6444 to −1.682, and from −3.665 to −3.943 kJ/mol), and Ea (9.277, 5.060, and 12.10 kJ/mol), the adsorption of OG dye on the aforementioned nano-adsorbents, respectively, was found to be endothermic, spontaneous, and physisorption process. In addition, because of the relatively high adsorption capacity and chemical stability, the as-synthesized α-Fe2O3 adsorbent is suggested as a promising candidate for the removal of OG textile dye from aqueous solutions.

MgO nanostructure via a sol-gel combustion synthesis method using different fuels: An efficient nano-adsorbent for the removal of some anionic textile dyes

Magnesium oxide nanostructures were synthesized via a sol-gel combustion method using urea, oxalic acid, and citric acid fuels. The effect of the fuel type on the products was studied. The as-prepared products were characterized by means of FE-SEM, HR-TEM, XRD, and FT-IR analyses. The results exhibited that the used fuels gave MgO products with different morphologies, and the oxalic acid fuel produced pure MgO nanoparticles with the smallest crystallite size (ca. 12nm). The adsorption properties of the MgO products for the removal of Reactive Red 195 (RR195) and Orange G (OG) anionic dyes were examined. Using a batch method, various parameters affecting the adsorption properties were studied. The results revealed that MgO nanostructure generated from the oxalic acid fuel had the highest adsorption capacities (207 and 21.5mg/g for RR195 and OG dyes, respectively). Additionally, the adsorption data followed the pseudo-second-order kinetic model and Langmuir adsorption isotherm model. And the adsorption process was controlled by intra-particle diffusion, bulk diffusion, and film diffusion mechanisms. Besides, the thermodynamic study showed that the adsorption of the textile dyes of interest on the as-prepared MgO nanostructures was an exothermic, physisorption and spontaneous process.

Cobalt ferrite nanoparticles via a template-free hydrothermal route as an efficient nano-adsorbent for potential textile dye removal

We have reported herein the preparation of a pure cobalt ferrite (CoFe2O4) nanostructure, as an efficient nano-adsorbent, via a template-free hydrothermal and post thermal conversion route.

Hydrothermal tuning of the morphology and particle size of hydrozincite nanoparticles using different counterions to produce nanosized ZnO as an efficient adsorbent for textile dye removal

The current study aimed to investigate the effect of counterions on hydrothermally synthesized hydrozincite (zinc hydroxide carbonate), which was thermally converted to generate ZnO nanostructures, which are an efficient nanoadsorbent for the removal of Reactive Black 5 (RB5) dye from wastewater. Hydrozincite nanospheres and flower-like structures were hydrothermally prepared using various zinc salts (sulfate, acetate, and nitrate) and ammonium carbonate in a molar ratio of 1:3, respectively, at 120 °C for 3 h. The morphology and crystallite size of the hydrozincite precursor were effectively controlled via the parameters of the hydrothermal reaction. Interestingly, sulfate was the optimum counterion, as zinc sulfate salt produced pure hydrozincite nanospheres with the smallest crystallite size (∼13.57 nm), which were consequently thermally decomposed at 400 °C for 1 h to produce pure nanosized ZnO (∼10 nm). The compositions of the as-synthesized products were determined by means of FT-IR, FE-SEM, HR-TEM, XRD, zeta potential, BET, and thermal analyses. An adsorption study showed a much higher adsorption capacity (80.9 mg g−1) of the as-prepared ZnO nanoparticles toward RB5 dye. The adsorption of RB5 dye followed pseudo-second-order kinetics. In addition, the equilibrium adsorption of RB5 dye was best described by a Langmuir isotherm model and the calculated thermodynamic parameters, ΔG0 (from −4.027 to −7.533 kJ mol−1), ΔH0 (30.798 kJ mol−1), and Ea (29.105 kJ mol−1), indicate the spontaneous, endothermic, and physisorptive nature of the adsorption process.

Benzenesulfonic acid-grafted graphene as a new and green nanoadsorbent in hydrogen sulfide removal

Benzenesulfonic acid-grafted graphene (BS-rGO) was synthesized through a three-step reaction, characterized, and employed as a highly efficient nanoadsorbent for hydrogen sulfide removal. The materials including precursors and final adsorbent were fully characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier-transform infrared (FT-IR) spectroscopy, and atomic force microscopy (AFM). The operational conditions of 4000–6000 h−1 space velocities and 60,000 ppm H2S feed concentrations were examined on adsorption capacity. Furthermore, temperature optimization within the range of 30–70 °C was set which significantly improved the adsorption capacity of the nanoadsorbent. After 3 h, the amount of H2S output concentration by GO, rGO, and BS-rGO was found as 369 ppm, 488 ppm, and 220 ppm, respectively. Hydrogen sulfide adsorption analysis showed a good result to eliminate the H2S using nanoadsorbent.

Poly(acrylic acid)-zeolite nanocomposites for dye removal from single and binary systems

In this research, nanocomposites of zeolite/acrylic acid were synthesized with different amount of acrylic acid (AA) as monomer and ammonium persulfate (APS) as an initiator to remove cationic dyes from wastewater in single and binary systems. Basic Red 46 (BR46) and Basic blue 41 (BB41) were used as the cationic dyes. The surface characteristics of nanocomposites were investigated using Fourier transform infrared spectra (FTIR) and scanning electron microscope. FTIR results confirmed successful attachment of acrylic acid on the zeolite surface. The influence of different factors such as initial monomer concentration and amount of initiator on dye removal in single system, and adsorbent dosage, pH, and initial dye concentration in single and binary systems were evaluated. The dye adsorption isotherm and kinetics were studied. Results indicated that adsorption of BR46 and BB41 onto nanocomposites is well fitted with Langmuir isotherm and the rate of sorption was found to conform to pseudo-second-order kinetic with good correlation. The maximum dye adsorption capacity (Q0) of composites for two different amounts of AA and APS in nanocomposite (0.17 mmol AA + 3.50 mmol APS and 0.26 mmol AA + 6.57 mmol APS) was 2,439.02 and 2,702.70 for BB41, 2,272.72 and 2,380.95 mg/g for BR46 in single system, 2,083.33 and 2,127.65 for BB41, 1,785.71 and 1,923.07 mg/g for BR46 in binary system. Results illustrated that zeolite/acrylic acid nanocomposites could be suggested as an efficient nanoadsorbent to remove cationic dyes from wastewaters.

A new strategy for hydrogen sulfide removal by amido-functionalized reduced graphene oxide as a novel metal-free and highly efficient nanoadsorbent

In this research, hydrogen sulfide is adsorbed on amido-functionalized reduced graphene oxide (AFRGO) as a nanoadsorbent. By the use of n-propylamine and allylamine, reduced graphene oxide (RGO) was amidated for the adsorption of hydrogen sulfide. The materials were characterized by adsorption of H2S, potentiometric titration, scanning electron microscopy (SEM), Fourier-transform infrared (FT-IR) spectroscopy, and X-ray diffraction (XRD) analysis. The effect of the operational conditions of 4000–6000 h−1 space velocities and 60,000 ppm H2S feed concentrations were examined on adsorption capacity. The results show that H2S feed concentration, space velocity, and functional groups of adsorbents have a major effect on H2S adsorption. It was also found that the temperature in the range of 30–70°C had a significant effect on H2S adsorption. The concentration of H2S adsorbed in 3 h by AFRGO containing allyl substituent, AFRGO containing propyl substituent, graphene oxide (GO), and reduced graphene oxide (RGO) were reported as 59,710, 59,650, 59,600, and 59,500 ppm, respectively. Hydrogen sulfide adsorption analysis showed that nanoadsorbents increase adsorption capacity of H2S.