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CM-HPEI-HD-1, prepared by modifying HD-1 resin with HPEI and sodium chloroacetate, is a promising adsorbent with good performance and good stability for adsorption of In(iii).

The PA–HPEI–OACF constructed with PA, HPEI, and ACF displays excellent performance in the adsorption and separation of In(iii).

In this study, low-cost and easily obtained biochar was chosen to prepare nickel-modified biochar materials (Ni/BC) through a one-step activation pyrolysis method. Characterization with X-ray diffraction, X-ray photoelectron spectroscopy and high-resolution transmission electron microscopy proved the existence of Ni

In this work, two hyperbranched polyethyleneimine (HPEI) based gels were prepared and employed as adsorbents for the removal of dyes. HPEI-MBA gel was obtained by a cross-linking reaction between HPEI and N, N′-methylene-bis-acrylamide (MBA). And HPEI-MBA gel was further treated with isobutyric anhydride to form thermoresponsive HPEI-MBA-IBAm gel having important application in aspect of desorption of dyes. The structure and morphology of gels were characterized by FTIR, XPS, SEM and BET. Many different affecting factors for adsorption capacity of gel, such as contact time, pH, concentration of dyes and adsorptive selectivity, were investigated. The HPEI-MBA gel demonstrated a satisfactory adsorption capacity for methyl orange (MO) and xylenol orange (XO) as high as 1552.76 mg/g and 3312.06 mg/g, respectively. Interestingly, the HPEI-MBA gels had a considerable adsorption capacity for mixed system of anionic and cationic dyes by regulating the value of pH. In the MO/methylene blue (MB) mixture system, the adsorption capacities of gels for MO and MB were all higher than that of single-dye system, and in the MO/basic fuchsin (BF) mixture, the adsorption capacity for MO and BF can be improved under neutral condition. In the MO adsorption process, the adsorption/desorption kinetic of HPEI-MBA and HPEI-MBA-IBAm gels exhibited a good fit to the pseudo-second-order model. Meaningfully, the adsorption efficiency of HPEI-MBA gel for MO was still as high as 93.52% after 11 cycles of adsorption/desorption. More importantly, we developed a general and facile method to achieve dye desorption by adjusting temperature which relies on the temperature-sensitive properties of HPEI-MBA-IBAm. Therefore, the HPEI-MBA gels and HPEI-MBA-IBAm gels, as a new recycle adsorbent, could have comprehensive application in the removal of dyes from wastewater.

Many colorimetric sensors based on noble metal nanoparticles for the detection of mercury ion (Hg2+) have attracted widespread interest from academia in recent years. A critical issue is how to realize the detection of Hg2+ with high sensitivity and selectivity. A novel colorimetric sensor based on AgNPs stabilized by linear thermoresponsive poly(N-isopropyl acrylamide) (PNIPAm) was developed for the application of detecting Hg2+ with a color change from yellow to taupe brown due to the formation of Ag–Hg core–shell nanoparticles. The AgNP/PNIPAm sensor exhibited good selectivity and high sensitivity (LOD = 75 nM) with a good linear relationship not only in the ultrapure water (R2 = 0.9903) but also in the tap water (R2 = 0.9905). More importantly, based on the thermosensitivity of PNIPAm, this sensor could also achieve the separation of Ag–Hg composites with enriching efficiencies of 97.60% and 95.40% for Ag and Hg, respectively, which can avoid serious secondary pollution. Therefore, this dual-functional nanocomposite has important potential implications in the detection and separation of Hg2+.

As an emerging class of nitrogenous disinfection by-products, halonitromethanes have caused public health concerns owing to their high toxicity. More and more attention has been paid to the new materials and technologies for the removal of halonitromethanes. In this study, a novel material, nanoscale zero-valent iron (nZVI) supported on MIL-96 (nZVI@MIL-96) with favorable stability and reusability, was synthesized and applied to the adsorption-degradation of trichloronitromethane (TCNM) in the water. The results revealed that almost all the TCNM could be removed under 20 mg/L nZVI@MIL-96 dosage with a wide temperature range. The optimum mass ratio of nZVI to MIL-96 was 1:2, and the TCNM adsorption-degradation followed a pseudo-first-order model. The coexisting ions, such as SO42–, PO43–, and NO3–, with high concentration brought adverse effects on the removal of TCNM; however, the effects of Cl– and CO32– were insignificant. The concentrations of aluminum and iron ions in water were all within the standard value after adsorption with the nZVI@MIL-96. The degradation mechanism of TCNM by nZVI@MIL-96 included two steps, namely, adsorption and degradation, and methylamine was the terminal dechlorination and denitration products. In a word, the as-prepared nZVI@MIL-96 nanoparticles demonstrated the capabilities as a material of adsorption-degradation of TCNM in the water.

In this paper, the primary amine extractant (N1923) was modified by phytic acid (PA), and then a novel solvent impregnated resins (SIRs) were prepared using PA modified N1923 as the extractant and styrene-divinylbenzene type macroreticular resin (HZ–803) as the support. Adsorption performance and adsorption mechanism of SIRs for In (III) was studied from hydrochloric acid medium. The SIRs were characterized by FTIR, SEM, BET, TGA and XPS. The effect of mass fraction of PA, solution pH, adsorbent dosage, adsorption time, initial concentration of In(III) and adsorption temperature on adsorption was investigated. The adsorption capacity of SIRs for In(III) was enhanced by PA modified N1923. When the mass fraction of PA was 33.3%, SIRs have the highest adsorption capacity at pH of 3.13. The adsorption process can be well described by the pseudo second-order model and Langmuir isotherm model, and the adsorption of In(III) on SIRs is endothermic process. The FTIR and XPS spectra of SIRs before and after adsorption indicate that the amine group and the phosphate group are the functional groups for adsorption of In(III). In addition, the adsorption selectivity of SIRs for In(III) was also investigated at different pH. The SIRs can preferential adsorb In(III) in two components system (In(III)/Cu(II), In(III)/Zn(II), In(III)/Fe(II)) and quaternary components system (In(III)/Cu(II)/Fe(II)/Zn(II)).

Cross-linked amino-starch (CAS) was prepared via a dry process and used to adsorb glyphosate from aqueous solution. Effects of adsorption time, glyphosate concentration, temperature, pH, and ionic strength on the adsorption of glyphosate by CAS were thoroughly studied. It shows that CAS can effectively remove glyphosate from the solution. The adsorption equilibrium is attained in about 60 min, and the adsorption process follows the pseudo second-order kinetic model. Sips isotherm model is more suitable than Langmuir and Freundlich isotherm models for the adsorption process, and the maximum adsorption capacity is 3.61 mmol·g–1 from Sips isotherm fitting. The result of thermodynamics study indicates that the adsorption is a spontaneous and exothermic process. The results of isotherm and thermodynamics study show that the adsorption of glyphosate by CAS is attributed to a combination of chemical and physical processes. The adsorption process is severely affected by pH and ionic strength of the solution and t...

A new colorimetric method of detecting Hg2+ in aqueous solutions was proposed, based on the three color changes of gold nanoparticles (AuNPs) with the assistance of ascorbic acid (AA) and multi-sulfhydryl functionalized hyperbranched polyethylenimine (SH-HPEI). The mechanism of sensing is based on the formation of Au-Hg alloy and its aggregation, along with the corresponding three color changes from red (AuNPs) through sandy beige (Au-Hg alloy) to celandine green (larger Au-Hg alloy). Compared with usual colorimetric assays with only one color change progress from red to blue or red to purple of reported AuNPs, this assay is highly selective for Hg2+ detection due to the fact that the appearing probability of identical three color changes triggered by interfering agents or the possibility of false positive results is very, very low. The detection limit of 8.76 × 10−9 M is lower than the guideline value of Hg2+ (30 nM) in drinking water defined by the World Health Organization (WHO). Meanwhile, the concentration range (from 8.76 × 10−9 to 1.27 × 10−4 M) of this new detection method is the widest one that has been reported. Moreover, this method is successfully applied to detecting Hg2+ in real water sample. More importantly, this novel colorimetric sensor based on multiple color changes may open a new avenue for the development of Hg2+ sensing probes.

Tannic acid (TA) film covered magnetic microspheres (Fe3O4@TA–Fe3+) was synthesized and applied for removal of Pb2+and Hg2+ from aqueous solution. The resulted Fe3O4@TA–Fe3+ was characterized with thermo-gravimetric analysis, vibrating sample magnetometer, transmission electron microscope, and Fourier transform infrared spectra. The adsorption of pollutants was pH dependent because the complexation of TA with Fe3+ was disassembled at low pH. The composites showed high maximum adsorption capacity for Pb2+ up to 1115.3 mg/g and Hg2+ to 279.4 mg/g. Furthermore, the Fe3O4@TA–Fe3+ composites could be easily separated from the solution by a magnet after adsorption because of the excellent superparamagnetic property. Thermodynamics study indicated that the adsorption of Pb2+ and Hg2+ on Fe3O4@TA–Fe3+ sorbents was spontaneous, chaotic degree decreasing and endothermic process. The present results warrant the promising application of magnetic Fe3O4@TA–Fe3+composites for removal of Pb2+ and Hg2+ from contaminated water, and this study is the first application of TA film in environmental remediation.

The hyperbranched polyethylenimine (HPEI) derivative with thiol (SH) terminals was synthesized and used as multidentate ligand to stabilize AuNPs/analyte composites. A facile and rapid colorimetric method for the sensitive and selective detection of Ag+ based on the formation of Au-Ag core-shell NPs with three color changes (red through brown to green) was developed. Successive multiple color changes can greatly improve the specificity and selectivity of this colorimetric sensor owing to the lower possibility of false positive results. Other environmentally relevant metal ions did not interfere with the determination of Ag+. The response (i.e., the absorbance at 600 nm, A600 nm) was linearly proportional to the Ag+ concentration in a range from 8.76 × 10−9 to 1.27 × 10−4 M with a detection limit of 8.76 × 10−8 M by the naked eyes and 8.76 × 10−9 M by the UV–vis spectra. For the first time, this novel colorimetric sensor based on multiple color changes was developed and successfully applied to detect Ag+ in real samples.

A novel solvent-impregnated resin (SIR) with trialkylphosphate Cyanex 923 as extractants and macroporous resin HZ830 as substrate was prepared to adsorb In(III) from HCl solutions. The effects of HCl concentration on adsorption were investigated within the range of 0.5 to 7 mol L− 1, and results showed that adsorption capacity was greatest at 2 mol L− 1 HCl. The adsorption mechanism of In(III) in chloride medium suggested that In(III) was apt to be adsorbed as a neutral species InCl3. As the anionic species InCl4− it tended to be adsorbed in the form of ion pairs combined with protons. The extraction stoichiometry of In (III) with SIR was studied, and the extracted species were found to be InCl3·nL and HInCl4·nL (n = 2, 3). The isothermal adsorption of In(III) fit the Langmuir model. Kinetic data indicated that the adsorption process was consistent with a pseudo second order model, and the sorption rate was mainly controlled by an intraparticle diffusion step. A column experiment showed that In(III) could be eluted from SIR with 2 mol L− 1 sulfuric acid, and the SIR showed good stability and reusability after five adsorption-elution cycles. When the SIR was applied for In(III) adsorption from waste liquid crystal display (LCD) leaching solution containing 102.15 mg L− 1 In(III), the adsorption efficiency exceeded 90% with 0.30 g adsorbent.

SiO2 was coated on the surface of Fe3O4 nanoparticles through hydrolyzation of Na2SiO3, and then thiol groups were modified on SiO2 by silanization reaction to form Fe3O4@SiO2–SH sorbents. Due to high affinity between thiol group and mercury, the Fe3O4@SiO2–SH was applied as magnetic sorbent for in situ extraction and stabilization of trace mercury species from natural water. Trace Hg2 + and methylmercury in 500 mL of water sample could be almost recovered with only 60 mg sorbents. Magnetic separation and rapid adsorption equilibrium greatly simplified extraction procedure and shortened analysis time. Solution pH had no obvious effect on mercury recoveries in the range of 3–9. The loaded Hg2 + and methylmercury were readily desorbed with 2.5 mL of 0.5 mol L− 1 HCl containing 1% thiourea. The mercury speciation in eluate was acquired by using high-performance liquid chromatography-inductively coupled plasma mass spectrometry (HPLC-ICP-MS). The detection limits of the present method for Hg2 + and methylmercury were 1.0 and 0.3 ng L− 1, respectively. The recoveries of spiked water samples were in the range of 96%–104% with relative standard deviations varying from 0.2% to 4.2%, showing good accuracy of the method.

Three GO-HPEI gels were prepared by a cross-linking reaction of graphene oxide (GO) with hyperbranched polyethylenimines (HPEIs) with different molecular weight. The GO-HPEI gels are different from the most reported GO-based materials and have superior adsorption performance because that these gels have more adsorption sites over using the common cross-linking agent (especially double-functionality or tri-functionality monomer). The morphology and structure of the GO-HPEI gels were characterized by FTIR, XRD, SEM, TEM, BET, TGA and elemental analyses. The adsorption property of Pb(II) onto GO-HPEI gels and the factors that influence the adsorption, such as the Pb(II) concentration, contact time and pH value, were investigated. The GO-HPEI gel exhibited an adsorption capacity as high as 438.6 mg g −1 for Pb(II) ions, and its insolubility in water makes the separation from wastewater easy. Adsorption experiments demonstrated that the amino groups and the cross-link density affect the adsorption capacity. In the Pb(II) adsorption process, the adsorption kinetic and equilibrium data were well simulated with the pseudo-second-order and Langmuir isotherm models. The adsorption capacity of the GO-HPEI gel for Pb 2+ only exhibited a slight decrease after eight cycles of adsorption/desorption, indicating its good stability. Therefore, the GO-HPEI gels could serve as promising adsorbents for potential application in the removal of Pb(II) from wastewater.

The adsorbent 8-hydroxyquinoline-modified PGMA (HQPGMA resin) was synthesized via “graft from” method. The adsorption and desorption performances for Pb(II) were investigated in detail. The maximum uptake was determined at 1.38 mmol g−1 with an initial concentration of Pb(II) 0.02264 mol L−1, pH 5.81, and temperature 25°C. The equilibrium time of adsorption kinetics for Pb(II) was 600 min. The adsorption process conformed to pseudo-second-order model. Film diffusion was the rate-limit step. Freundlich model fits the adsorption isothermal process. The thermodynamic parameters implied the adsorption was exothermic and spontaneous. Pb(II) adsorbed on the resin can be eluted by a range of concentrations of hydrochloric acid from 0.2 to 0.8 mol L−1 solution. The optimal concentration of hydrochloric acid solution was achieved with 0.4 mol L−1, which resulted in a desorption rate of 92.38%. The resin demonstrated reusability with same effect after three times of adsorption/desorption cycles.

Here we have developed a facile and rapid colorimetric method for the sensitive and selective detection of Ag(+) based on the non-aggregation of gold nanoparticles (Au NPs) capped with hyperbranched polyethylenimine derivatives. In the detection process, an unusual colour change from red to brown was observed due to the formation of Au-Ag core-shell nanoparticles, which was more sensitive than that of the usual colorimetric assays (red to blue) based on the aggregation of Au NPs. After the colour changed, the non-aggregation-based Au-Ag core-shell nanomaterials did not aggregate further and could remain stable for a long time, which was convenient to record, detect and observe. The sensing probe exhibited a drastically long observing time for detecting Ag(+) owing to the stability of the Au-Ag core-shell non-aggregates, high sensitivity with a low detection limit of 8.76 nM by the naked eye and 1.09 nM by using a UV-vis spectrophotometer and a good linear relationship within the range from 1.09 to 109 nM. The colour change of the system is very fast, occurring within 1 to 2 minutes. Moreover, the proposed method also showed a remarkably high selectivity toward Ag(+) and was successfully used in tap water and drinking water samples. Therefore, this unusual colorimetric assay based on the non-aggregation of Au NPs has a great potential as a simple, rapid, sensitive and selective detection method for the detection of Ag(+).

A strategy for enriching, separating and detecting Hg2+ based on thermoresponsive hyperbranched polyethylenimine (HPEI) with isobutyramide (IBAm) end groups (HPEI-IBAm) capped gold nanoparticles (AuNPs) is reported. The thermoresponsive AuNPs can enrich approximately 94.5% of Hg2+ in solution, with higher enriching efficiency than that toward Ni2+, Cu2+, Mn2+, Pb2+ and Cr3+ heavy metal ions. The enriched Hg2+ can be separated by simple stratification or centrifugation. By virtue of the specific amalgam of reduced mercury(II) ions with thermoresponsive HPEI-IBAm capped gold nanoparticles (AuNPs), an unusual color change from red to fawn can be used as a colorimetric probe to detect Hg2+ with a limit of detection (LOD) of 8.8 nM by the naked eye and 1.1 nM by a UV-vis spectrophotometer. Importantly, this colorimetric sensor based on the formation of non-aggregated Au–Hg alloy stabilized by thermoresponsive HPEI-IBAm is more sensitive than that of the usual colorimetric sensors (red to blue) based on aggregation of AuNPs. After the color changed, the Au–Hg alloys did not aggregate further and could remain stable for a long observation time due to the stabilizing effects of HPEI-IBAm, which was convenient to record, detect and observe. The sensing process is very fast with a response time of less than 0.5 minutes. In addition, the proposed method showed an excellent selectivity for Hg2+ and was successfully applied in tap water and drinking water samples. Therefore, this strategy for the first time achieved simultaneous enrichment, separation and detection of Hg2+ based on the thermoresponsive HPEI-IBAm/AuNPs composite, which has the potential application for environmental renovation and groundwater analysis.

Hierarchical flower-like Bi2Te3 was synthesized through a facile solvothermal method. The crystal structure and morphology of the as-prepared samples were characterized by X-ray diffraction (XRD), filed emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), and high resolution TEM. The reaction parameters such as reaction time, the amount of glucose, concentration of NaOH and the reaction temperature were systematically investigated. Based on the FESEM observations, a possible mechanism defined as a self-assembly process accompanied by anisotropic growth mechanism was proposed. Moreover, the thermoelectric properties were measured at the temperature range of 300–600 K. The hierarchical flower-like Bi2Te3 presented good thermoelectrical properties. The maximum ZT value reached up to 0.6 at 600 K, which was higher than that of Bi2Te3 nanoparticles.

Hierarchical Bi 2 S 3 hollow spheres have been synthesized by a facile solvothermal process in the presence of sodium tartrate. The hollow spheres are composed of numerous ultrathin nanorods with the average diameter of 15 nm. Based on the time dependent electron microscope observations, the formation mechanism of such hierarchical structures has been proposed as a sodium tartrate directed self-assembled process and oriented attachement mechanism. The morphology and size of the subunits can be controlled by adjusting the amount of sodium tartrate. The Nitrogen adsorption-desorption measurements suggest that mesopores exist in these hollow spheres. The as-derived Bi 2 S 3 hollow spheres exhibit excellent electrochemical hydrogen storage properties.

A solvent impregnated resin (SIR) with sec-octylphenoxy acetic acid (CA-12) impregnated on a styrene-divinylbenzene copolymer support (HZ818) was first prepared. To improve the stability of the first SIRs for indium adsorption, a novel type of SIR (NSIR) had been prepared by forming a PVA–boric acid protective layer on the first SIR containing CA-12. The NSIR and SIR were characterized, and their adsorption behavior for indium(III) were compared by batch and column methods in a hydrochloric acid medium. Both the NSIR and SIR showed high adsorption capacities for In(III) at pH 3.0, and the maximum adsorption capacities increased with temperature. The Langmuir isotherm and pseudo second-order model fit the experiment data well at different temperatures. The NSIR showed better stability and reusability than the SIR. It is possible to separate In(III) from a mixed solution containing Zn(II), Cu(II), Cd(II) and In(III) at pH 3.0 from hydrochloric acid medium with SIR and NSIR.

In this work, ultrathin Sb2Se3 nanowires as well as the sulfur doped nanosheets are synthesized by a facile solvothermal method through changing the volume of thioglycollic acid. The growth process of the nanoarchitectures and the effects of reaction parameters are investigated systematically by X-ray powder diffraction (XRD), field emission scanning electron microscopy (FESEM) and transmission electron microscope (TEM). Based on the experimental results, the formation mechanism of the Sb2Se3 nanosheets is proposed as a thioglycollic acid directed anisotropic growth process combined with an Ostwald ripening mechanism. Moreover, the electrochemical properties of the products are measured, the sulfur doped Sb2Se3 nanosheets show the superior performance and better stability than those of ultrathin Sb2Se3 nanowires.

Hierarchical pinetree like Bi2S3 was synthesized through a facile solvothermal route in the mixture of deionized water and tetrahydrofuran. The phase composition, morphology, and structure of the as-prepared Bi2S3 products were characterized by using various techniques including X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and transmission electron microscopy (TEM). It was found that the pinetree like Bi2S3 structures were composed of numerous assembled nanosheets, which had uniform morphology with the mean width and length of about 110 nm and 15 μm, respectively. Furthermore, the electrochemical property of the obtained pinetree like Bi2S3 was investigated. The pinetree like Bi2S3 presented both the high electrochemical hydrogen storage and electrochemical Li intercalation performance.

In this paper, pH-sensitive polyelectrolyte complex micelles assembled from two oppositely charged graft copolymers chitosan-g-poly(N-isopropylacrylamide) (CS-g-PNIPAM) and sodium alginate-g-poly(N-isopropylacrylamide-co-N-vinyl-pyrrolidone) [ALG-g-P(NIPAM-co-NVP)] were prepared for controlled release of 5-fluorouracil (5-FU). The polyelectrolyte complex micelles showed a narrow size distribution with core-shell structure, where the core formed from positively charged CS and negatively charged ALG by electrostatic interactions. The hydrogen bonding interactions between micelles and 5-FU improved the drug loading. Changing temperature or pH, a controlled drug release was observed. Glutaraldehyde, as a chemical cross-linking agent, was used to improve the micelles stability and decrease the initial burst release. Cytotoxicity assays showed that drug-loaded micelles retained high cell inhibition efficiency in Hela cells. These novel complex micelles with environmentally sensitive properties are expected to be useful in the field of intelligent drug delivery system.

In this work, hierarchical flowerlike Bi2S3 structures constructed by polycrystalline nanoplates combined with urchinlike and wirelike Bi2S3 were synthesized by using a thioglycolic acid assisted solvothermal method. On the basis of the time-dependent experimental results, an anion exchange process and a self-assembly mechanism were proposed to account for the growth mechanism of the synthesized flowerlike Bi2S3. In addition, the morphology and the crystalline nature of the products can be easily tuned by changing the reaction temperature. Moreover, the electrochemical properties (electrochemical hydrogen-storage and lithium-intercalation performance) of the products were studied. The flowerlike Bi2S3 possesses both higher electrochemical properties and better cycle stabilities compared to urchinlike and wirelike Bi2S3.

A novel magnetic nanomaterial was developed for gold recovery from dilute solutions. Fe3O4 nanoparticles were prepared by co-precipitation method, and SiO2 was coated on Fe3O4 nanoparticles by hydrolyzation of Na2SiO3 for protecting the core from being oxidized or dissolved under acid solution, and then thiol groups were modified on the Fe3O4@SiO2 through silanization reaction. Characterization with transmission electron microscope (TEM), energy-dispersive spectroscope (EDS), and X-ray photoelectron spectroscopy (XPS) proved that SiO2 and thiol groups were successfully covered on the surface of Fe3O4 nanoparticles to form Fe3O4@SiO2-SH adsorbent, which was readily separated from solution with a magnet because of superparamagnetism of Fe3O4 core. The formation of the stable Au–S bond between thiol group and gold element could be applied for gold recovery from solution. The adsorption behavior of Fe3O4@SiO2-SH for gold followed Langmuir isotherm model, and the maximum adsorption capacity was 84.75 mg/g at pH 5. When the initial concentration of gold was 5 mg/L, the gold in solution was completely adsorbed by Fe3O4@SiO2-SH, and when the gold concentration was 10 mg/L, 98.8% gold was adsorbed. With the solution pH increasing from 3 to 7, the adsorption capacity for gold showed a slight decrease, and the adsorbents still remained good adsorbability under high salinity condition. Gold loaded on the adsorbent could be easily desorbed by 1 mol/L or 2 mol/L HCl containing 2% of thiourea, and the adsorbents showed good reusability after 5 times recycle.

Hierarchical chlorophytum-like Bi2S3 nanostructures are produced successfully on the large scale by a solvothermal method in the mixture of water and tetrahydrofuran. The crystal structure and morphology of the product are determined by X-ray diffraction (XRD) pattern, field emission scanning electron microscope (FESEM), and transmission electron microscopy (TEM). Time-dependent SEM observations indicate that the structure evolution of Bi2S3 contains self-assembly process and anisotropic growth mechanism. Furthermore, the electrochemical measurements present that the hierarchical Bi2S3 architectures display high electrochemical hydrogen storage and electrochemical Li intercalation performance.

The SiO2 shell was coated on Fe3O4 nanoparticle by hydrolyzation of Na2SiO3, and then thiol groups were modified on the Fe3O4@SiO2 through silanization reaction to form Fe3O4@SiO2–SH sorbents. Characterization with transmission electron microscope (TEM), Energy-dispersive spectroscope (EDS), and X-ray photoelectron spectroscopy (XPS) proved that SiO2 and thiol groups were successfully covered on the surface of Fe3O4 nanoparticle. The Fe3O4 core possessed superparamagnetism for magnetic separation, and the SiO2 shell could protect the Fe3O4 core from being oxidized or dissolved under acid solution and provide good modificability. Due to the strong interaction between mercury and thiol groups, the synthesized sorbents exhibited high adsorption capacity and good anti-interference ability during mercury adsorption. The maximum adsorption capacity calculated from Langmuir fitting was 148.8 mg/g at pH 6.5, and the sorbents still maintained good adsorption ability at low solution pH and high concentration of coexisting cations. Mercury loaded on the sorbents could be easily desorbed with 1 mol/L HCl containing 3 wt.% of thiourea, and the sorbents showed good reusability. The adsorption capacities were still kept over 110 mg/g in tested natural water samples, showing practical significance in remediation of mercury contaminated actual water.

Three solvent impregnated resins (SIRs) were first prepared using two types of nonreactive polystyrene-divinylbenzene polymers (HZ818 and HZ830) and one type of reactive weak basic ion exchange resin (D301) as supports and HEHEHP (2-ethylhexyl phosphonic acid mono(2-ethylhexyl) ester) as the extractant. Then the first two prepared SIRs were coated by poly-vinyl alcohol (PVA)-H3BO3 to improve their stability. The two types of coated SIRs were called HZ818-CSIR and HZ830-CSIR, and the third type of SIR was called D301-SIR. The three adsorbents were characterized by scanning electron microscopy and infrared spectrometer. The adsorption properties of iron (III) with three adsorbents were studied by batch method from sulfuric acid medium in the range of pH 0.9–1.9. The optimal pH values of all adsorbents were found at 1.5, and the saturated adsorption capacities of HZ818-CSIR, HZ830-CSIR and D301-SIR were determined as 16.7 mg·g− 1, 15.9 mg·g− 1 and 25.6 mg·g− 1 at 298 K, respectively. The adsorption isotherms were found to be fitted with Langmuir isotherms. The adsorption kinetic behaviors of HZ818-CSIR and HZ830-CSIR were fitted with pseudo-second-order kinetic model, while that of D301-SIR with Lagergren first-order kinetic model. The adsorption mechanisms of the three adsorbents were investigated with methods of saturation, equimolar series change and infrared adsorption spectra. It was found that the adsorption mechanism of Fe(III) with HZ818-CSIR and HZ830-CSIR could be deduced as cation exchange between Fe3 + and H+ from P-OH of HEHEHP accompanied with coordination between Fe(III) ion and the phosphoryl oxygen from HEHEHP. While for the D301-SIR, only a cation exchange between Fe3 + and H+ from P-OH of HEHEHP can be proposed.

A novel and simple method for preparing magnetic biomass activated carbon (BAC) was developed. The BAC was prepared by decomposing fallen leaves, and magnetic nanoparticles were grown in situ on BAC using solvothermal method. The prepared magnetic BAC was characterized with FT-IR, XRD, vibrating sample magnetometer, thermo-gravimetric apparatus, SEM, and high-resolution transmission electron microscope, and results indicate that BAC and magnetic nanoparticles were combined together successfully. To investigate the adsorption ability of the composites, several dyes were selected as sample pollutants, and the sorbent showed high adsorption capacity for the dyes. The solution pH had no significant effect on the adsorption in the range of 5–9. The adsorption behavior of magnetic BAC for dyes followed the Langmuir isotherm model, and the adsorption capacity of congo red, neutral red, and methyl green were 396.8, 171.2, and 403.2 mg/g, respectively. The maximum adsorption capacity in natural water showed no obvious decrease, indicating the strong anti-interference ability of the sorbents. The Gibbs free energy calculated from the thermodynamics data was negative, demonstrating that the adsorption of these dyes on the magnetic BAC was spontaneous. The magnetic BAC showed a great potential for the removal of dye pollutants from environment water.

A modified solvent impregnated resin (MSIR) was prepared by impregnation of sec-octylphenoxy acetic acid (CA-12) on styrene–divinylbenzene copolymer support (HZ818) after nitration of the benzene rings present in its structure. The MSIRs were characterized by thermogravimetric and Fourier Transform infrared spectroscopy (FTIR) analysis. The adsorption behavior of indium(III) on MSIRs was examined by batch and column method in hydrochloric acid medium. It was shown that optimal pH for indium(III) adsorption was 3.0. The adsorption isotherms were found to follow Langmuir model at different temperatures, and the maximum adsorption capacity enhanced with increasing temperature. The value of enthalpy change was positive, indicating that the adsorption of indium(III) with MSIRs is endothermic. Kinetic data indicated that the adsorption of indium(III) was in a good agreement with the pseudo second-order rate equation. The MSIRs sustained adsorptivity well after three recycles comparing with the SIRs.

A thiosemicarbazide resin based on polyvinyl chloride (TPV) was synthesized via the reaction between polyvinyl chloride supported diethylenetriamine (PVC-DETA) and CS2/thiosemicarbazide. Its structure was characterized by elemental analysis and infrared spectra analysis. The adsorption properties for the single ion solutions of Cu(II), Zn(II), Cd(II), Pb(II), Hg(II), Ag(I), Au(III), and binary ion solutions containing Ag(I) or Au(III) were studied. Experimental results indicate that TPV shows high adsorption selectivity for Ag(I) and Au(III). Specifically, the selectivity coefficients for the competitive adsorption of Ag(I) or Au(III) on TPV are ∞, 10.25, 10.92, 34.00, 11.33, and 11.17 from Ag(I)/Zn(II), Ag(I)/Cd(II), Ag(I)/Hg(II), Au(III)/Cu(II), Au(III)/Zn(II), and Au(III)/Pb(II) binary solutions, respectively. Furthermore, adsorption kinetics and adsorption isotherms of Ag(I) and Au(III) on TPV were thoroughly investigated. The pseudo-second-order kinetic model provides a better correlation of the expe...

In the present study, the nonlinear analysis method was used to evaluate the kinetics and equilibrium for Cd(II) adsorption on crosslinked starch phosphate (SP) from aqueous solution. The pseudo-first-order, pseudo-second-order and Elovich kinetic models were applied to test the kinetics experimental data, and the pseudo-first-order kinetic model provides a best correlation of the experimental data. Adsorption equilibrium data were fit by Langmuir, Freundlich, Dubinin-Radushkevich, and Sips isotherms. The results show that the data are best described by the Sips isotherms with a maximum adsorption capacity of 2.00 mmol/g. The effects of initial pH, and SP dose on the Cd(II) adsorption were also investigated. The adsorption capacities of Cd(II) on SP increase with the pH increasing from 2.0 to 8.0.

The aim of this research was to estimate the adsorption performance of water-insoluble starch sulfate (SS) for cationic dyes. Toluidine blue (TB), as a model cationic dye, was used to prepare an adsorbate solution. The effects of adsorption time, initial TB concentration, temperature, and initial pH on the adsorption of TB by SS were studied, and the kinetics and equilibrium of the adsorption process were investigated using a nonlinear analysis method. The results showed that SS can effectively remove TB from the aqueous solution. The adsorption kinetic data correlate well with the pseudofirst-order kinetic model. The Langmuir, Freundlich, Toth, and Sips isotherm models were applied in the adsorption equilibrium study. The Toth isotherms had the best applicability to describe the TB adsorption and show that the adsorption energies follow a heterogeneous distribution. The maximum adsorption capacity from the Toth isotherm fitting is 26.56 mg·g−1. The results of thermodynamics studies show that the adsorpti...

Coated solvent impregnated resins (CSIRs) had been prepared by the formation of PVA–boric acid protective layer on solvent impregnated resins (SIRs) containing 2-ethylhexyl phosphoric acid mono (2-ethylhexyl) ester (EHEHPA). The CSIRs were characterized by scanning electron microscopy, thermogravimetric analysis and FTIR analysis. The adsorption behavior for indium (III) was carried out with the CSIRs by batch and column method. Various parameters affecting the adsorption of indium (III) such as solution pH, ionic strength, contact time, indium ion concentration and flow rate were studied, respectively. The optimal pH for the adsorption of indium ion was found to be 1.5 in the sulfuric acid system. The indium (III) loaded on CSIRs could be effectively eluted by hydrochloric acid solution (0.5–2.0 mol L − 1 ), and the recovery was over 98.9%. The sorption isotherms were found to fit with Langmuir and Freundlich isotherms, respectively. The kinetics data indicated that the adsorption process of indium (III) with CSIRs followed Lagergren first order rate model. Separation of indium (III) from binary solution was also carried out successfully. The performance of the CSIRs nearly remained constant while the uncoated solvent impregnated resins (UCSIRs) rapidly lost the capacity after seven times recycling.

A new environment friendly adsorbent, cross-linked starch sulfate (CSS), was prepared and used to adsorb aniline from aqueous solution. Different adsorption parameters like initial pH, adsorption time, equilibrium aniline concentration, and temperature were thoroughly studied, and the kinetic, equilibrium, and thermodynamics of the adsorption process were further investigated. It showed that CSS can effectively remove aniline from the solution. The adsorption capacity is highly dependent on the amount of sulfate groups on adsorbents and the initial pH. The pseudo-first-order and pseudo-second-order kinetic models were applied to test the experimental data, and the pseudo-second-order kinetic model provided a better correlation of the experimental data in comparison with the pseudo-first-order model. The maximum removal efficiency of aniline is 75.29% using 1 g L−1 of CSS3 dose. Langmuir, Freundlich, Dubinin−Radushkevich, and Sips models have been applied to study the adsorption equilibrium, and the equili...

Double-responsive core-shell-corona complex micelles for applications in drug release were formed from self-assembly of two diblock copolymers PtBA-b- PNIPAM and PtBA-b-P4VP. The two diblock copolymers coaggregated into core-shell complex micelles in acidic water with the hydrophobic PtBA blocks as the common core and soluble PNIPAM/P4VP blocks as the mixed shell. Increasing temperature or pH value, the micelles converted into core-shell-corona micelles because of the collapse of PNIPAM or P4VP blocks as the inner shell and soluble P4VP or PNIPAM chains stretching outside as the outer corona. The anti-inflammation drug naproxen (NAP) was loaded as the model drug in micelles in acidic water and released because of the ionization of NAP in alkaline solutions. Compared with pure core-shell micelles, release of NAP from core-shell-corona complex micelles avoided the burst diffusion and the release rate is more easily controlled by tuning the composition of the mixtures or by adjusting the pH of the medium.

The enrichment of valuable metals from sulfuric acid leach liquors of various nickeliferous oxide ores has been investigated. Suitable enrichment processes based on sulfide precipitation and the Na-jarosite process have been tested and proved to be effective for recovering Ni, Co, and Cu from high-magnesium and high-iron pregnant liquors. Once the major impurities of magnesium and iron had been separated from the valuable metals, the resulting concentrated sulfate solutions mainly containing valuable metals (Ni, Co, and Cu) could be used for further metal separations by solvent extraction methods. It is hoped that such sequences may also be applied for the recovery and enrichment of valuable metals from dilute pregnant leaching liquors.

Methyl vinyl ketone (MVK) was first used to successfully copolymerize with acrylonitrile (AN). This was achieved by using azobisisobutyronitrile as the initiator. Differential scanning calorimetry results of the degradation of AN/MVK copolymers in air are presented. The apparent activation energy of degradation of the copolymers was calculated with Kissinger method. Effects of copolymerization conditions on the apparent activation energy of the copolymers were studied. It has been found that increasing dimethyl sulfoxide concentration in the solvent mixture leads to a rapid increase in the degradation apparent activation energy of AN/MVK copolymers. The apparent activation energy decreases quickly along with increase in the comononer MVK concentration, and this change becomes less prominent as the weight ratio of MVK/AN goes beyond 7/93. The apparent activation energy shows a trend of increase as the copolymerization temperature increases. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 1386–1390, 2007

The reverse atom transfer radical polymerization (RATRP) technique using FeCl 3 /iminodiacetic acid (IMA) complex as a catalyst was applied to the living radical polymerization of acrylonitrile (AN). A hexa-substituted ethane thermal initiator, diethyl 2,3-dicyano-2,3-diphenylsuccinate (DCDPS), was firstly used as the initiator in this iron-based RATRP system. The polymerization in N , N -dimethylformamide not only shows the best control of molecular weight and its distribution but also provides rather rapid reaction rate with the ratio of [AN]:[DCDPS]:[FeCl 3 ]:[IMA] at 500:1:2:4. The rate of polymerization increases with increasing the polymerization temperature and the apparent activation energy was calculated to be 49.9 kJ mol −1 . The polymers obtained were end-functionalized by chlorine atom, and they were used as macroinitiators to proceed the chain extension polymerization in the presence of FeCl 2 /IMA catalyst system via a conventional ATRP process. The resultant polyacrylonitrile fibers were obtained with the fineness at 1.16 dtex and the tenacity at 6.01cN dtex −1 .

The reverse atom-transfer radical polymerization (RATRP) technique using CuCl2/2,2′-bipyridine (bipy) complex as a catalyst was applied to the living-radical polymerization of acrylonitrile (AN). 1,1,2,2-Tetraphenyl-1,2-ethanediol (TPED) was first used as the initiator in this copper-based RATRP initiation system. A CuCl2 to bipy ratio of 0.5 not only gives the best control of molecular weight and its distribution, but also provides rather rapid reaction rate. The rate of polymerization increases with increasing the polymerization temperature, and the apparent activation energy was calculated to be 53.2 kJ mol−1. Because the polymers obtained were end-functionalized by chlorine atoms, they were used as macroinitiators to proceed the chain extension polymerization in the presence of CuCl/bipy catalyst system via a conventional ATRP process. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3529–3533, 2007

FeCl3 coordinated by iminodiacetic acid (IMA) was Changed used for the first time as the catalyst in azobisisobutyronitrile-initiated reverse atom-transfer radical polymerization (ATRP) of acrylonitrile (AN). An FeCl3 to IMA ratio of 1:2 not only gave the best control of molecular weight and its distribution but also provided a rather rapid reaction rate. The effects of solvents on the polymerization of AN were also investigated. The rate of the polymerization in N,N-dimethylformamide (DMF) was faster than in propylene carbonate or toluene. The molecular weight of polyacrylonitrile agreed reasonably well with the theoretical molecular weight in DMF. The rate of polymerization increased with increasing polymerization temperature and the apparent activation energy was calculated to be 54.8 kJ mol−1. The reverse ATRP of AN did not show obvious living characteristics with CuCl2 instead of FeCl3. Copyright © 2005 Society of Chemical Industry

Methyl vinyl ketone was firstly used to successfully copolymerize with acrylonitrile. This was achieved by using azobisisobutyronitrile as the initiator, and dimethyl sulfoxide as the solvent. Effect of copolymerization systems on monomer apparent reactivity ratios for copolymer of acrylonitrile with methyl vinyl ketone was studied for contrast. Values of monomer apparent reactivity ratios were calculated by Kelen–Tudos method. It has been found that the apparent reactivity ratios in aqueous suspension polymerization system were similar to those in solution polymerization system at polymerization conversion less than 20%. Beyond 50% of conversion, the changes of monomer apparent reactivity ratios become less prominent. In water-rich reaction medium [(H2O/dimethylsulfoxide (DMSO)>80/20), monomer apparent reactivity ratios were approximately equivalent to those in aqueous suspension polymerization system. In DMSO-rich reaction medium (DMSO/H2O > 80/20), apparent reactivity ratios were similar to those in solution polymerization system. Values of apparent reaction ratios both decreased when AN/MVK copolymer was synthesized in DMF and DMAc. The values of apparent reaction ratios gradually tend to 1 with increasing the copolymerization temperature. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4045–4048, 2006

A single-pot atom transfer radical polymerization was used for the first time to successfully synthesize polyacrylonitrile with a molecular weight higher than 80,000 and a narrow polydispersity as low as 1.18. This was achieved with CuBr/isophthalic acid as the catalyst, 2-bromopropionitrile as the initiator, and N,N-dimethylformamide as the solvent. The effects of the solvent on the polymerization of acrylonitrile were also investigated. The induction period was shorter in N,N-dimethylformamide than in propylene carbonate and toluene, and the rate of the polymerization in N,N-dimethylformamide was fastest. The molecular weight of polyacrylonitrile agreed reasonably well with the theoretical molecular weight in N,N-dimethylformamide. When chlorine was used in either the initiator or the catalyst, the rate of polymerization showed a trend of decreasing, and the molecular weight deviated from the theoretical predication significantly. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 3372–3376, 2006