High Adsorption Capability Research Articles

Magnetic poly(cyclotriphosphazene-co-4,4′-sulfonyldiphenol) nanotubes modified with glacial acetic acid for removing methylene blue: Adsorption performance and mechanism

Developing excellent dye adsorbent with high adsorption capability and good reusability and clarifying the interaction mechanism between adsorbent and adsorbate are highly desired for eliminating water pollution. Herein, we present a novel magnetic adsorbent Fe3O4/poly(cyclotriphosphazene-co-4,4′-sulfonyldiphenol) nanotube modified by glacial acetic acid (defined as Gl-PZSNTs-Fe3O4) to remove cationic dye methylene blue (MB) from aqueous solution. Compared with the unmodified magnetic PZSNTs-Fe3O4, the Gl-PZSNTs-Fe3O4 exhibits rapid adsorption rate and high adsorption capacity. The adsorption equilibrium data was fitted well with Langmuir model, and the adsorption kinetics obeyed the pseudo-second-order kinetics model and Elovich model. Thermodynamic analysis showed that the MB adsorption onto the Gl-PZSNTs-Fe3O4 was endothermic and spontaneous. Especially, through contrasting the adsorption behavior of Gl-PZSNTs-Fe3O4 and PZSNTs-Fe3O4 towards MB dye, we highlighted the importance of glacial acetic acid modification for enhancing the adsorption capacity of the Gl-PZSNTs-Fe3O4. Meanwhile, we also proposed the adsorption mechanism of the Gl-PZSNTs-Fe3O4 towards MB dye.

Harvesting of blooming microalgae using green synthetized magnetic maghemite (γ-Fe2O3) nanoparticles for biofuel production

This study aims to harvest the hazardous algae from water using biologically synthetized magnetic nanomaterials with cheap, simple and environmentally friendly process to valorise it into biodiesel. The characteristics of obtained nanoparticles showed that it has 50 nm-sized hexagonal or round-shaped nanoparticles indicating its high adsorption capability due to its large surface area (78.4 m2 g−1) and suitable porous volume (0.3 cm3 g−1), and thus, proved to be effective to collect microalgae from water. The optimum conditions for harvesting efficiency (HE) were determined under a response surface methodology (RSM) using CCD approach (five-level, four-factor Central Composite Design) including various parameters; particle dosage, time, stirring speed and temperature while considering the HE (%) as the response. The optimized conditions for HE were found to be 56 mg L−1 particle dosage, 48 s, 310 rpm and 22.5 °C. The optimized algae HE was 82.4%. The lipid content of the harvested biomass was 5.6%. The produced oil was found to have high saturation level in which butyric (C4:0) (43.4%), heneicosanoic (C21:0) (22.4%), heptadecanoic (C17:0) (16.7%) and undecanoic (C11:0) (12.8%) acids were found as the dominant fatty acids. Fatty acid methyl esters (FAME) composition of obtained biodiesel was suitable comprising of 40.46% saturated fatty acids, 42.77% monounsaturated fatty acids and 16.77% polyunsaturated fatty acids. The physicochemical properties of the produced biodiesel were characterized. All properties, except acid value, satisfy international ASTM D6751 criteria and can be used commercially with acid neutralization.

Indolocarbazole based polymer coated super adsorbent polyurethane sponges for oil/organic solvent removal

The synthesis of an indolocarbazole-fluorene based conjugated polymer (ICZP6), by Sonogashira coupling reaction, has been presented. The ICZP6 has then been integrated with a nano iron oxide embedded polyurethane foam (ICZP6PUF) to develop a promising adsorbent for oil/organic contaminants in aqueous systems. The anchoring ability of ICZP6 on to iron oxide PU sponge switches on significant hydrophobicity within the whole molecular assembly. The cooperative effects of ICZP6-iron oxide- PU sponge system have been highlighted in terms of structural, microscopic and wettability characteristics. The heterogeneity and hierarchical porous structure of the system offer a high adsorption capability for different types of oils and organic contaminants in water, typically in the range of 100–240 gg-1. The performance of ICZP6PUF has been confirmed by the fast (within 5–10s) and choosy removal of selected oils and organic solvents from polluted water with the aid of an external magnetic field. The adsorbed materials (oil/organic solvents) can be separated from the adsorbent by simple mechanical squeezing without causing any structural deformation or performance deterioration; with a reusability of the system over 50 cycles. The adsorption isotherm has been found to fit well with the Langmuir model with R2 = 0.9484. To extent the scope of the ICZP6PUF hybrid, an integrative logic gate has been designed.

Dioxide/Chitosan/poly(lactide-co-caprolactone) composite membrane with efficient Cu(II) adsorption

Herein, titanium dioxide/chitosan/poly(lactide-co-caprolactone) (TiO2/CS/P(LLA-CL)) composite membranes with highly efficient adsorption of copper ions (Cu(II)) in aqueous solution were developed, through a facile electrospinning method. First, TiO2 nanoparticles were ultrasonically dispersed in CS/P(LLA-CL) solution to get a uniform suspension. Afterwards, the mixture was applied for electrospinning to generate the smooth and bead-free composite membranes. The high adsorption capability of the composite membranes on Cu(II) was mainly attributed to the combination of TiO2 nanoparticles, CS/P(LLA-CL) matrix and nanosized membrane. Among those, the TiO2/CS/P(LLA-CL) composite membrane with 2% TiO2 content demonstrated the maximum adsorption capability (˜190.5 mg g−1) for Cu(II) from aqueous solution. Their adsorption behaviors were well conformed to pseudo-second-order kinetic model and Langmuir isotherm model. Moreover, FTIR and XPS results confirmed the existed chelation and ion exchange between the membrane and the Cu(II) during adsorption process. Due to its simplicity, effectiveness and stability in water, this type of composite membrane may serve as a promising environmentally-friendly and non-toxic adsorbent for removal of Cu(II) in aqueous.

THE ADSORPTION OF HEAVY METALS FROM INDUSTRIAL WASTEWATER USING SARGASSUM CRASSIFOLIUM

Sargassum crassifolium is the origin strains of macroalgae from Indonesia which was the most effectively adsorb heavy metals from liquid solution and it was investigated the adsorptive capability of heavy metals in industrial wastewater. The macroalgae were collected at Kotok Besar Island, Seribu Island, North Jakarta, Indonesia and were treated with the variety of pH 2, 3, 4, 5 and 9 for 60 minutes oscillation, in duplicate assessment. The macroalgae were selectively effective for removal of Cd, Hg, and Pb compared with other heavy metals, achieving 75-99.05% adsorption efficiency, mostly in acidic condition for 60 minutes oscillation, except Hg. The selectivity order for other metal ion uptake by S. crassifolium was Cu>Fe>Co>Ni>Cr with percentage removal below 56%. Due to the low cost, availability and significantly high adsorption capability, the brown macroalgae S. crassifolium is able to be used for selective removal of heavy metals from industrial wastewater effectively in acidic pH range

Application of cress seed musilage magnetic nanocomposites for removal of methylene blue dye from water

A magnetic nanocomposite adsorbent based on cress seed mucilage (CSM) was synthesized for removing methylene blue (MB) cationic dye from aqueous solutions. These adsorbent nanoparticles were prepared by in situ formation of magnetic iron oxide nanoparticles (MIONs) coupled with CSM mucilage and benefited from the advantages of both CSM and MIONs. The CSM-MIONs adsorbent exhibited a great dye adsorption capacity along with a strong magnetic character. The effect of various experimental parameters were studied on the adsorption performance of CSM-MIONs including pH, ionic strength, initial dye concentration, contact time and temperature. The adsorbent nanoparticles were characterized by FTIR, FESEM, XRD, DLS, and VSM techniques. Thermodynamic analysis indicated that the studied dye adsorption process has a spontaneous and exothermic nature. The equilibrium adsorption data were in agreement with the Langmuir kinetic model (R2 > 0.99) and described by the pseudo-second-order Langmuir equation (R2 > 0.98). It was revealed that intraparticle diffusion is not the only rate controlling factor. The CSM-MIONs adsorbents could be well regenerated using an acid solution, and showed high adsorption capability even after five desorption–adsorption cycles. The obtained results showed that the CSM-MIONs can potentially be used as a high-performance low cost adsorbent in wastewater treatment.

Efficient removal of Sr(II) from aqueous solution by melamine-trimesic acid modified attapulgite composite

Melamine (MA)-trimesic acid (TMA) modified attapulgite (ATP–TMA–MA) with high adsorption capability for Sr(II) was successfully synthesized using attapulgite (ATP) as a matrix via a facile two-step approach. Batch adsorption experiments indicated that the adsorption kinetics followed the pseudo-second-order equation and isothermal adsorption data fitted well with the Freundlich isotherm model. The adsorption thermodynamic analysis indicated that Sr(II) adsorption onto ATP–TMA–MA was a spontaneous and endothermic process. Sr(II) adsorption mechanism of ATP–TMA–MA was mainly decided by chemisorption. TMA–MA molecules grafted on ATP surface markedly improve the removal efficiency of ATP–TMA–MA for Sr(II).

Influences of multiple clay minerals on the phosphorus transport driven by Aspergillus niger

Phosphorus (P) is a major limiting nutrient for plant growth. Clay minerals are able to work as active centers in soil system due to their high surface area and CEC. Yet, effects of clay minerals on P biogeochemical cycle driven by microorganisms are still unclear. In this study, hydroxylapatite and three typical clay minerals (kaolinite, palygorskite, and montmorillonite) were incubated with Aspergillus niger to investigate microbial influences on P release and adsorption. Due to the mineral particles, hyphae wrapped small montmorillonite particles (<10 μm, confirmed by SEM and TEM), which promoted microbial bioactivities, e.g., respiration and acid production. P consumption by the fungus lowered the available P from 143 to 68 ppm. Meanwhile, ATR-IR spectra and HPLC analysis confirmed the intense adsorption of oxalic acid (the primary microbial secretion) onto montmorillonite. Despite the higher acid production, both the high adsorption capability of the clay and the acid consumed by phosphate dissolution caused that pH values increased from ~2 to ~4 after montmorillonite addition. In contrast, low CEC, dispersibility, and surface area of kaolinite and palygorskite limited their ability to enhance microbial activities and the subsequent interactions with hyphae. Therefore, clay minerals, especially montmorillonite, can drive P transport with the favor from fungi in ecosystem.

Realization of super high adsorption capability of 2D δ-MnO2 /GO through intra-particle diffusion

Due to the high specific surface area and unique pore properties, two-dimensional materials (2D) are promising candidates in adsorption. In this work, 2D δ-MnO2 is synthesized through one-step self-assembly and its adsorption properties to methylene blue (MB) are examined. The maximum adsorption amount achieved 267.6 mg/g, it is far high beyond adsorbents reported previously which have similar structures. Considering the unique properties of GO, the prepared 2D MnO2 is combined with GO to enhance the adsorption capacities further. The combined compounds exhibit super high adsorption capabilities and the adsorption amount of 2D δ-MnO2/GO to MB increased to 1432.0 mg/g, which is more than 5 times higher than that of 2D δ-MnO2, the significant increase of adsorption amount is owing to the increase of pore size, which initiates the intra-particle diffusion channel. The adsorption kinetics and adsorption isotherms of 2D MnO2 and 2D δ-MnO2/GO are also analyzed with pseudo-second-order model and Langmuir isotherm model at different equilibrium concentration respectively.

New efficient selective adsorbent of tobacco specific nitrosamines derived from discarded cigarette filters

Abstract To expand the application of the principle of selective adsorption, new hierarchical porous carbon was fabricated from cigarette filters and cheap metal salts via one-pot synthesis, in order to selectively capture the tobacco-specific nitrosamines (TSNA) in solution. The type and amount of metal salt in the carbon precursor took charged of pore texture, electrical property and morphology, forming a new sorbent beyond activated carbon and zeolite in the selective liquid adsorption of TSNA. With the amount of FexO-doped of 10%–16.5%, new carbon sorbent captured the 29.4%–33.8% of TSNA in the tobacco extract solution though the solution contained thousands of components. Moreover, it exhibited a zeolite-like selectivity to remove 93% of 4-methylnitrosamino-1-3-pyridyl-1-butanone (NNK). The hierarchical sorbents combined the high adsorption capability of mesopore and the shape-selectivity of micropore, based on waste utilization and simply controllable process, offering a clue for preparation of new hierarchical material and resource regeneration and environmental protection.

PBA-loaded albite-base ceramic foam in application to adsorb harmful ions of Cd, Cs and As(V) in water

PurposeThe purpose of this paper is to provide an investigation on a new kind of adsorbent materials, namely, the Prussian blue analog (PBA)-loaded albite-base porous ceramic foam, which can effectively adsorb the heavy metal ion in the wastewater.Design/methodology/approachThe natural zeolite powder has been used as the primary raw material to make a sort of porous ceramic foam by impregnating polymer foam in slurry and then sintering. Adjusting the technological parameters could control the bulk density of the ceramic product, which could float on water with the bulk density less than 1 g/cm3 and also sink in water with the bulk density higher than 1 g/cm3. After desilicating the porous ceramic foam, an Al-Fe type PBA with a strong function of ion exchange was loaded on the ceramic surface by directly yielding.FindingsThe adsorption performance for harmful metal ions was greatly improved by combining together the high adsorption capability of the PB analog and the efficient high specific surface area of the porous ceramic foam.Originality/valueThis work presents a PBA-loaded albite-base porous ceramic foam that can effectively adsorb the harmful substance in water, and the adsorption efficiency for some typical harmful ions, i.e., Cd2+, Cs+ and As(V), was examined under different conditions of the experimental period, the pH value and the ion concentration in the tested solution.

Highly Porous Carbon Xerogels Doped with Cuprous Chloride for Effective CO Adsorption.

Carbon monoxide (CO) has long been recognized as a metabolic waste and toxic gas and is also the most common asphyxiating poison that seriously endangers human health. Thus, an adsorption material with high CO adsorption capability is urgently needed. In this study, carbon xerogels (CXs) doped with CuCl were prepared via a sol–gel method and a facile soaking process. The CuCl-doped CXs show the highest CO adsorption capacity of 12.04 cc/g, which is much higher than those of the undoped CXs and activated carbon. Such a high adsorption capacity of the CuCl-doped CXs is not only because of their high porosity but also because of the chemical adsorption induced by CuCl. Moreover, these CuCl-doped CXs exhibit high desorption rate (∼79%), which is beneficial for repeatability.

Removal of hexavalent chromium in soil by lignin-based weakly acidic cation exchange resin

Abstract The adsorption of Cr(VI) from soil onto lignin-based weakly acidic cation exchange resin (LBR) has been investigated. Lignin is a three-dimensional amorphous polymer composed of methoxylated phenylpropane units. The unique structure and chemical properties render the lignin suitable for the remediation of hexavalent chromium in the soil. Soil column leaching experiments were conducted to optimize the adsorption conditions. The effects of contact time, pH, adsorbent dosage and temperature on the adsorption of Cr(VI) onto the LBR have been investigated. Experiment data were then correlated with Freundlich and Langmuir isotherms. The Langmuir isotherm model fits the experimental data better than the Freundlich isotherm. It was found that the LBR has a high adsorption capability for Cr(VI) (3.95 mg·g−1) with a removal rate of 91.9%. Thus, LBR can serve as a good absorbent for the reduction of the concentration of Cr(VI) in soil.

Insight into the efficient TSNA capturer derived from zeolite Hβ

The thermal regeneration of zeolite Hβ adsorbed tobacco specific nitrosamines (TSNA) along with the impact of zeolitic pore size on the liquid adsorption of TSNA were investigated in this article for the first time. After calcination at 873 K, the regenerated Hβ zeolite exhibited a kind of self-activation to trap more TSNA in succeeding adsorption in tobacco solution, achieving the high capacity of 225 μg g−1. With the assistance of TG-MS technique, it was clear that no secondary pollution of volatile nitrosamines (VNA) occurred in the regeneration of Hβ zeolite. In order to seek cheap TSNA-capturer, three zeolites with different pore structures, Hβ, MCM-22 and NTY (the dealuminated NaY) zeolites were assessed in the TSNA adsorption in laboratory formulated surface water and tobacco solution to examine the influence of pore size. MCM-22 was the excellent selective sorbent of 4-methylnitrosamino-1-3-pyridyl-1-butanone (NNK), but its channels were easily clogged in tobacco solution. Zeolite Hβ showed a prominent TSNA adsorption in both solutions due to its pore size of 0.6–0.7 nm. The cheap zeolite NTY with the pore size of 0.74 nm exhibited a high adsorption capability of TSNA similar to Hβ in tobacco solution, making it a promising replacement for industrial applications.

Graphene oxide-based hydrogels as a nanocarrier for anticancer drug delivery

Graphene oxide (GO) possesses excellent mechanical strength, biocompatibility, colloidal stability, large surface area and high adsorption capability. It has driven to cancer nanotechnology to defeat cancer therapy obstacles, via integration into three-dimensional (3D) hydrogel network with biocompatible polymers as nanocomposites carrier, and controllable release of anticancer drugs. Specifically, the surface of GO affords π-π stacking and hydrophilic interactions with anticancer drugs. Additionally, modification of GO with various polymers such as natural and synthetic polymers enhances its biodegradability, drug loading, and target delivery. In this review, GO based hydrogels research accomplishments are reviewed on the aspects of crosslinking strategies, preparation methods, the model drug, polymer conjugation and modification with targeting ligands. Moreover, swelling kinetics, drug release profile and biological activity in vivo and in vitro are discussed. The biocompatibility of GO based hydrogels is also discussed from the perspective of its nano-bio interfaces. Apart from that, the clinical potential of GO based hydrogels and its major challenges are addressed in detail. Finally, this review concludes with a summary and invigorating future perspectives of GO based hydrogels for anticancer drug delivery. It is anticipated that this review can stimulate a new research gateway to facilitate the development of anticancer drug delivery by harnessing the unique properties of GO based hydrogels, such as large surface area, chemical purity, high loading capacity of drug, chemical stability, and the nature of lipophilic for cell membrane penetration.

ADSORPTION OF URANIUM SIMULATION WASTE USING BENTONITE:TITANIUM DIOXIDE

ADSORPTION OF URANIUM SIMULATION WASTE USING BENTONITE TANIUM DIOXIDE. Bentonite is a clay material of high surface area that have galleries within its structure. Bentonite that is modified with TiO2 will have high adsorption capability. In this study, natural bentonite and bentonite:TiO2 were characterized with FTIR, XRD and BET instruments to determine functional group, basal spacing, and specific surface area. This study also investigates the adsorption of bentonite:TiO2 in various environmental factors, such as pH (pH 1, 3, 5, and 8), contact time (10, 20, 30, 40, 50, 60, 70, 90, and 120 min), and initial uranium concentration (20, 40, 60, 80 ppm), and their influences on adsorption capacity, and determine the kinetics equation and adsorption isotherm. Based on FTIR analysis, a decrease in the band of O-H bond from water molecule was observed, which indicates the presence of TiO2 in bentonite interlayer structure. The XRD characterization of bentonite:TiO2 does not show diffraction peak in 001 plane. This is due to delamination of bentonite interlayer structure. Delamination is caused by the presence of TiO2 in large quantities, thus damaging the bentonite interlayer structure into irregular sheets. Bentonite as sheets will cause the basal spacing to increase and it is anticipated that XRD will find it difficult in detecting the 001 plane at a low 2 theta angle. The surface area of bentonite:TiO2 has increased by 12.04 m2/g. The maximum adsorption capacity of U(VI) took place at pH 5.0 for 70 minutes contact time and uranium concentration of 60 ppm. In this study, the adsorption kinetic and adsorption isotherm are pseudo second-order kinetic and Langmuir isotherm. The kinetic constant and maximum adsorption capacity of bentonite:TiO2 are 0.075 g/mg.min and 5.848 mg/g respectively.Keywords: Bentonite, TiO2, Adsorption, Uranium

Rapid adsorption of lead ions using porous carbon nanofibers

Lead is one of the toxic elements in the environment having non-biodegradable behavior. On the other hand, the high contamination of lead in water is a major alarming threat to the world nowadays. In this study, PAN-based porous carbon nanofibers (p-CNFs) were used to adsorb the lead ions for both batch and continuous method. The synthesis was achieved by electrospinning and thermal treatment. The characterization of p-CNFs was achieved via FE-SEM, EDX, BET and Raman spectra. Furthermore, the adsorption capability for lead ions was examined using ICP-MS. The adsorption parameters such as pH of the solution, the mass of nanofibers, adsorption time and initial concentration of lead ions were optimized. The obtained results fitted well with the Langmuir model and the pseudo-second-order model. The nanofibers showed high adsorption capability at neutral pH within 1 min. Therefore, the prepared p-CNFs can be recommended for lead ions removal up to its permissible limit in a continuous purification system for drinking water.

Rhenium-Metalated Polypyridine-Based Porous Polycarbazoles for Visible-Light CO2 Photoreduction

Transformation of CO2 into valuable chemicals and especially fuels is deemed as a promising approach to reduce our dependence on fossil fuels and to alleviate climate change. Carbazole-based porous polymers bearing rhenium-metalated polypyridine functionalities were constructed via simple oxidative coupling reaction. These porous polymers are employed as heterogeneous supports for immobilization of catalytically active rhenium complexes and furthermore provide high CO2 adsorption capabilities and light absorption abilities, i.e., photosensitizing properties. Consequently, such rhenium-metalated microporous polycarbazole networks show high efficiencies for CO2 photoreduction upon visible-light irradiation, with a CO evolution rate up to 623 μmol g–1 h–1 and selectivity of 97.8%. The microporous solid photocatalyst shows enhanced stability and photocatalytic performance compared to the molecular catalysts during long-term use.

Adsorption and On-Site Transformation of Transition Metal Cations on Ni-Doped AlOOH Nanoflowers for OER Electrocatalysis

AlOOH has long been used as excellent adsorbent for removal of heavy metal cations from wastewater. Herein we report one-pot synthesis of carboxylic-functionalized Ni-doped AlOOH nanoflowers (AlOOH NFs) with high adsorptive capability toward various transition metal cations, and more importantly, the AlOOH NFs adsorbed with various transition metal cations were for the first time directly used as electrocatalyst for oxygen evolution reaction (OER). By simply manipulating the initial metal cation concentration and their molar ratio, the OER catalytic performance of the resulting catalysts could be modulated. The lowest overpotential at a current density of 10 mA cm–2 prepared from AlOOH NFs adsorbed with FeIII and NiII is 0.32 V in 0.1 M KOH and 0.275 V in 1.0 M KOH. Such AlOOH-supported electrocatalyst demonstrates remarkable stability, which shows no evident increase of the overpotential at 10 mA cm–2 after 2 h of steady electrolysis at an overpotential of 0.42 V. The excellent OER electrocatalytic activ...

Arsenic removal from water by Zr-γ- FeOOH nanoparticles

Zr-γ-FeOOH nanoparticle adsorbent for As(V) and As(III) removal was prepared by a chemical co-precipitation method. Compared with γ-FeOOH, the addition of Zr enhanced the adsorptive capacities of As(V) and As(III). The maximum adsorptive capacities for As(V) and As(III) were 69.81 and 94.25 mg/g, respectively (rate Fe:Zr =1:0.5) at pH= 7.0. The adsorption data accorded with Langmuir and Freundlich isotherms. The adsorption of As(III) by Zr- γ-FeOOH was found to be effective in wide pH range of 6–8. Competitive ions hindered the adsorption according to the decreasing sequence phosphate, sulfate, ammonium, chloride, magnesium and calcium. The high adsorptive capability and good performance on other aspects make the Zr-γ- FeOOH nanorods a promissing adsorbent for the removal of As(V) and As(III) from groundwater.