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A mesoporous adsorbent was synthesized within a short time by a microwave-assisted method, and it showed high capacity and reusability for Pb(ii) adsorption.

Hollow red cell-like Na2Ti3O7/nitrogen-doped carbon are synthesized by a template-self strategy.

A novel preparative approach for promising cathode materials for capacitive deionization (CDI) is proposed. Several 3D Na4Ti9O20/N-doped carbon composite materials (3D NTO/N-C-x, x represents the hydrothermal reaction time) with high surface area are synthesized by pyrolysis of Ti-based metal–organic frameworks (Ti-MOFs) and a subsequent hydrothermal treatment strategy. Notably, the intrinsic interfacial interaction of the optimized 3D NTO/N-C-2 facilitates the synergy of the internal driving field and condensed phase interface, which is greatly beneficial to obtain more active sites for sodium ion storage and improved storage capacity (249 F g−1 at 1 A g−1). Furthermore, an all-faradaic-type 3D NTO/N-C-2//Ag@rGO full desalination cell shows high salt adsorption capacity (59.3 mg g−1) and stable cycling desalination ability (95% capacity retention rate over 20 cycles at 1.4 V). In addition, the mechanism of the zwitterion removal/release of the desalination cell is thoroughly investigated by electrochemical measurement. This work not only provides a reasonable strategy to establish cathode materials for CDI, but also may trigger the rapid development of Ti-based electrode materials in many frontier fields.

Herein, a thiourea cross-linked three-dimensional graphene aerogel (TCGA-1) was successfully prepared via a ring-opening reaction between the amino groups of thiourea molecules and the epoxy groups of graphene oxide (GO) sheets. Honeycomb-like three-dimensional porous morphology was confirmed by SEM, TEM, TGA, FT-IR, XPS, RS and XRD. The removal of heavy metal ions (Cu2+, Pb2+, Cr3+ and Cd2+) onto TCGA-1 was investigated with respect to solution pH, metal ion concentration and cycle time. In addition, it was also developed for the removal of anionic dyes (acid orange II and methyl orange) and cationic dyes (rhodamine B, methylene blue, and malachite green) from water. The results indicate that the removal of heavy metal ions onto TCGA-1 was greatly influence by pH. The sample can be regenerated more than twenty times based on their adsorption/desorption cycles, with a slight loss in the removal capacity. Malachite green or methylene blue (100 mg L−1) was completely removed using TCGA-1 within six hours and the removal behavior was described well using a pseudo-second-order kinetic model. It is also effective for removing other organic dyes used in this work. Therefore, the prepared broad-spectrum adsorbent exhibits satisfactory performance for many kinds of contaminants, suggesting its potential applications in the environmental cleanup.

Herein, a new persimmon tannin/graphene oxide (GO-PT-6Glu) composite was fabricated through one-step cross-linking method. The as-prepared GO-PT-6Glu has substantial phenolic hydroxyl groups (up to 5.23 mmol g−1) by introducing water-soluble PT (up to 5.50 mmol g−1) on the GO, which provides the opportunity to use it as an adsorption material to recover germanium. The GO-PT-6Glu was then used to adsorb germanium from aqueous solution and showed the highest than among currently reported adsorption capacity (117.38 mg g−1). Simultaneously, it exhibits excellent cycle performance to adsorb germanium still with a high adsorption efficiency (up to 81.42%) after 5 adsorption–desorption cycles. More importantly, the GO-PT-6Glu showed superior selectivity towards Ge(IV) as compared to As(III) (Cl−/SO42−/PO43−), in spite of the concentration of As(III) (Cl−/SO42−/PO43−) was 100 times higher than that of Ge(IV). Taking advantages of its low cost, selective adsorption, as well as environmental protection and high adsorption, the GO-PT-6Glu is expected to be the most promising material in recovery of Ge(IV) from water containing As(III).

In the present work, high density active sites (C N– groups) were introduced favorably onto the surface of silica by cross-linking reaction, leading to designing a new adsorbent and applying to the adsorption for Re(VII) from aqueous solutions. The novel adsorbent (SS-0.5h-0.5N-15GA) was characterized by SEM-EDS, TEM, FT-IR and XPS etc. The adsorption process fitted well with Langmuir isotherm the kinetic data fitted with pseudo-second order, and the experimental maximum adsorption capacity for Re(VII) was 270.13 mg/g at pH3.0, which was much higher than SS-0.5h-0.5N. Significantly, the reusability experiments demonstrated that SS-0.5h-0.5N-15GA exhibited excellent regeneration ability, with no obvious decline in adsorption capacity after four cycles. These results indicated that SS-0.5h-0.5N-15GA were promising for Re(VII) adsorption because of their higher rhenium adsorption capacity, rapid adsorption rate, low cost, and facile recovery process.

In order to replace extractant or resin prepared from petrochemical products, a series of carboxyl-functionalized materials based on natural corn stalk (x-IDA-EPI-OCS) were prepared. When the mass ratio of the EPI-OCS and iminodiacetic acid (IDA) was 1:3, the uptake capacity of Ga(III) on the modified corn stalk (3-IDA-EPI-OCS) from acidity solution could react 139.56 mg g−1. More importantly, the 3-IDA-EPI-OCS could completely separate Ga(III) from Ga(III)–As(III) or/and Ga(III)–Ge(IV) binary mixtures at pH > 2. By analyzing the results of acidity test as well as that of FTIR and XPS, the adsorption mechanism was deduced as cation exchange between Ga3+, Ga(OH)2+or Ga(OH)2+ and the hydrogen ions of carboxyl groups and/or hydroxyl groups. This study provided an effective and economical method for recovery of gallium ions from aqueous solution.

A series of xwt%Al-SBA-15 catalysts prepared by modified wetness impregnation was investigated for γ-valerolactone (GVL) decarboxylation to butene. It was found that the impregnation of Al species not only remained the ordered mesoporous structure of parent SBA-15, but also created large amounts of Bronsted and Lewis acid sites on the surface of catalyst. The considerable amount of solid acid sites and the suitable Bronsted/Lewis acid ratio endowed 2.23 wt%Al-SBA-15 catalyst an excellent catalytic performance. Under the optimized conditions, the GVL conversion and butene yield can reach 99.8% and 96.6% at 320 °C, respectively. Mechanism studies indicated that the decarboxylation of γ-protonated PEA controlled speed of the whole reaction. Moreover, the catalytic activity of regenerated 2.23 wt%Al-SBA-15 catalyst was satisfactory after eight cycle tests, and the butene yield could still reach 92.2%.

Reported powdery adsorbents with poor adsorption efficiency and stability make it imperative to develop novel materials to extract gallium ions (Ga(III)) from effluents. Herein, UiO-66-NH2-based mixed matrix membranes (TPU/0.1THB/U6N-1.5 MMMs) via electrospinning is firstly reported for separation and recovery of Ga(III). TPU/0.1THB/U6N-1.5 MMMs efficiently overcomes multiple bottlenecks of powder UiO-66-NH2, including poor stability, reusability and adsorption capacity. Its maximum adsorption for Ga(III) is 96.18 mg·g−1 at pH 10.0. It has superiority in selective adsorption of Ga(III) from Al(III), Cu(II), Zn(II), Co(II) coexistence solution. Adsorption capacity of TPU/0.1THB/U6N-1.5 for Ga(III) reaches more than 80% after 9 cycles. Specially, it still retains excellent mechanical strength, flexibility and structural integrity after 12 h filtration, or after 9 adsorption-desorption cycles, even soaked in 5 mol·L-1 HCl for a week. TPU/0.1THB/U6N-1.5 MMMs also improves the problem of low water flux. TPU/0.1THB/U6N-1.5 with high MOFs loading possess high water flux of 382.2 L·m−2·h−1 with a permance of 382.2 L·m−2·h−1·bar−1 and rejection rates of 90% for Ga(III). The main adsorption mechanism of TPU/0.1THB/U6N-1.5 is based on the chelation between phenolic hydroxyl groups of MMMs and Ga(III) at pH 10.0. Overall, the as-prepared TPU/0.1THB/U6N-1.5 has potential for water treatment through the process of membrane adsorption.

99Technetium (99Tc) is one of the most dangerous radioactive isotopes in the legacy nuclear waste, and harmful to the environment and human health. Effectively removing it remains a long-term challenge. Herein a resin-like imidazolium-based ionic liquid polymer (DVB-2C8VEIMBr) was prepared for selective adsorption of TcO4− (ReO4− as an alternative for laboratory operation). It is manifested that DVB-2C8VEIMBr integrates high adsorption capacity (313.28 mg·g−1) and selectivity (90.68% in 6000 times excess of SO42− ions). A real-scenario experiment exhibits DVB-2C8VEIMBr can remove up to 93% of TcO4− from the simulated Hanford LAW scrubber solution. More importantly, DVB-2C8VEIMBr displays super acid and alkaline resistance and stability after immersing for 8 months under extreme conditions of 3 M HCl and 2 M NaOH. It can also effectively separate rhenium from molybdenum solution in the range of 3 M HCl - pH 2. Additionally, it still showed perfect regeneration performance after 10 cycles. In particular, this work demonstrates the feasibility of imidazolium-based ionic liquid adsorbents in the TcO4− or ReO4− immobilization process, which can be applied to capture these radioactive oxygen anions under high acid and high alkali conditions.

Iron hydroxide/manganese dioxide doped straw activated carbon was synthesized for As(III) adsorption. The Fe-Mn-SAc adsorbent has two advantages, on the one hand, the straw active carbon has a large surface area (1360.99 m2 g−1) for FeOOH and MnO2 deposition, on the other hand, the manganese dioxide has oxidative property as a redox potential of (MnO2 + H+)/Mn2+, which could convert As(III) into As(V). Combined with the arsenic species after reacting with Fe-Mn-SAc, the As(III) transformation and adsorption mechanism was discussed. H2AsO4−oxidized from As(III) reacts with the Fe-Mn-SAc by electrostatic interaction, and unoxidized As(III) as H3AsO3 reacts with SAc and/or iron oxide surface by chelation effect. The adsorption was well-described by Langmuir isotherms model, and the adsorption capacity of As(III) was 75.82 mg g−1 at pH 3. Therefore, considering the straw as waste biomass material, the biosorbent (Fe-Mn-SAc) is promising to be exploited for applications in the treatment of industrial wastewaters containing a certain ratio of arsenic and germanium.

Extraction of rhenium into the ionic liquids phase from aqueous solutions was investigated using N235 as extractant. At temperatures from 293.15 to 318.15 K, the equilibrium molalities of ReO4– were measured at an ionic strength from 0.2 to 2.0 mol·kg–1 in the aqueous phase containing NH4Cl as supporting electrolyte. The standard extraction constants K0 at various temperatures were obtained by methods of the Pitzer polynomial approximation. Thermodynamic properties for the extraction process were calculated.

A series of ionic liquids based on trifluoroacetic acid, namely, [Cnmim][TFA] (n = 2, 3, 4, 5, 6) (1-alkyl-3-methylimidazolium trifluoroacetate), were designed and synthesized. The density, surface tension and refractive index were measured in the temperature range of 293.15 to 343.15 ± 0.05 K, and some physicochemical properties of the ILs were calculated. Using the concept of molar surface Gibbs free energy, the traditional Eotvos equation was improved into a modified Eotvos equation, in which the intercept and the slope represented the molar surface enthalpy and the molar surface entropy, respectively, for [Cnmim][TFA] (n = 2, 3, 4, 5, 6). The thermal expansion coefficient (α) of [Cnmim][TFA] was calculated according to the interstitial model, and the order of magnitude of the calculated values was in good agreement with the corresponding experimental values. A new hypothesis was proposed, stating that the interstitial molar surface Gibbs free energy (gs) is not determined by the type of IL. From the refractive index and the molar surface Gibbs free energy, an equation to predict the surface tension of ILs was derived and the predicted values were highly correlated with the corresponding experimental values. Finally, a new polarity scale for ILs was developed, and the polarity order of the [Cnmim][TFA] (n = 2, 3, 4, 5, 6) ILs was estimated.

We prepared a series of amino-functionalized organic-inorganic hybrid silica materials by post-modification (SBA-15-N) and one-pot (SS-0.5h-N) methods with different molar rate of APTES/SS (0.1:1, 0.2:1, 0.3:1, 0.5:1), and then took salicylaldehyde and epichlorohydrin as bridges, modified diisobutylamine on the hybrid silica to obtain the adsorbents containing tertiary amine groups. It was found that the combined use of organic and inorganic precursors (one-pot) destroys the ordered mesoporous structure, but the organic units distributed more homogeneously which conducive to the progress of adsorption. For the samples prepared by one-pot, the adsorption capacity increased dramatically when the molar rate of APTES/SS is 0.3:1 (SS-0.5h-0.3N-DIBA, 221.37 mg g−1), and the adsorption behavior obeys the Langmuir model. The adsorption mechanism could be electrostatic attraction and chelation effect between ReO4− and nitrogenous group which demonstrated by FT-IR and XPS. In addition, the SS-0.5h-0.3N-DIBA could effectively separate Re(VII) from coexisting metal ions (Cu(II), Zn(II), Mn(II)) at pH

In this study, we synthesized a series of diisobutylamine-functionalized graphene oxides as adsorbents (GO-DEA-DIBA) by adjusting synthetic conditions for the efficient adsorption of rhenium(VII) (Re(VII)). Results indicated that the best mass ratio was 10 mg of sodium carbonate to 5 g of distilled water, and a cooling time of 44 min could prevent the exfoliation of functional groups and achieve higher uptake capacity of Re(VII). The maximum uptake of Re(VII) was found to be 140.82 mg g–1 at 303 K with an initial Re(VII) concentration of 800 mg L–1. More importantly, it can be clearly seen that mixed ions (Cu2+, Zn2+, and Mn2+) could almost separate with Re(VII) on the adsorption of ReO4– onto the GO-DEA-DIBA with a weak acidity solution. Re(VII) was adsorbed on the GO-DEA-DIBA via charge interactions between tertiary amine groups and ReO4– by infrared spectroscopy and X-ray photoelectron spectroscopy analysis. In addition, adsorption behavior, adsorption isotherms, desorption, and regeneration are also d...

In this work, a facile and controllable multi-templating approach based on a solo nonionic surfactant P123 and peroxotitanic acid (PTA) was reported for the preparation of bimodal meso-mesoporous titania (BMM-TiO 2 ) with high surface area (150–243 m 2 g −1 ), high pore volume (0.3–0.6 cm 3 g −1 ), large mesopore sizes spanning from 8 to 16 nm (BJH pore size), and high & tunable crystallinity (Anatase or Anatase + Rutile). The BMM-TiO 2 was shown to be a homogeneous ‘mixture’ of two series of wormhole mesostructures with two modes of mesopore sizes that depend on both the contents of P123 and synthetic conditions. The formation of BMM structures was proposed to arise from both the formation of differentiated micellar structures of P123 (dual soft-templating) and their subsequent different mesostructural shrinkages driven by prolonged drying process ( i.e. , 100 °C for 12 h) in the presence of PTA. The low-temperature crystallization behaviours of PTA, unusual hard-templating effect of P123 and its carbon derivatives (3rd fold templating), large mesopores relative to the surrounding TiO 2 crystals are all believed to be responsible for the high thermal stability of the obtained BMM-TiO 2 . To our knowledge, it is for the first time reported that P123 plays such multiple templating roles (three folds in this work) in the preparation of meso-TiO 2 , not to mention that P123 was also confirmed to be a prerequisite for the formation bi-crystalline BMM-TiO 2 . In the photodegradation test of Rhodamine B in water by UV irradiation, other than the high surface area and synergistic effect between anatase and rutile phases, the BMM structures were also found to be advantageous to enhance the photocatalytic properties of mesoporous TiO 2 .

Four different silica mesostructures, SBA-15 with mesopore size (8.5 nm), SBA-15 with mesopore size (10.3 nm), mesocellular foam (MCF) with uniform cell size (33.2 nm), and MCF with bimodal mesoporosity, were grafted with aminopropyl groups and used for selective recovery of Mo(VI) from Re(VII)-containing effluent. Adsorption isotherms and mechanism of Mo(VI) adsorption on these materials were studied. The adsorbed complexes of Mo(VI) could be formed by ion exchange process or/and by chelation reaction. This study shows a new approach for fractional recovery and separation of Mo(VI) from Re(VII) by using amino-modified SBA-15-type mesoporous silica.

New strategies for adsorbing environmental pollutants such as Ag+ and organic dyes are still in urgent need. Based on this, we developed a highly efficient adsorbent, porous graphene-like carbon (PGC), by a simple catalysis process. A three dimensional porous graphene-like carbon hydrogel (3D-PGCH) was further obtained by introducing polyvinyl alcohol (PVA) and fully cross-linked via freeze-drying. The 3D-PGCH had a high adsorption capacity for Ag+ with an adsorption value of 234.32 mg g−1 at pH 4 and 303 K. Its active ingredient PGC exhibited excellent adsorbing effect on methylene blue (MB), and the maximum adsorption was up to 13381.62 mg g−1, about 32 times higher than that of using single PGC. Moreover, the adsorption-desorption experiment reflected a good recyclability of 3D-PGCH, whose adsorption capacity remained a high level after four cycle experiments. This study provides a positive choice for resource conservation and wastewater remediation.

With the ever-increasing of Rare Earth Elements (REEs) in various high technology applications, efficient recovery of REEs from liquid sources is becoming significantly important. In this work, ZIF-8 and UiO-66-NH2 (U6N) are combined to form a 3D-agaric like core-shell structure hybrid material (U6N@ZIF-8-20), which exhibits good performance in REEs extraction. Due to the abundant adsorption sites of ZIF-8 and the excellent water stability of UiO-66-NH2, 3D-agaric like U6N@ZIF-8-20 showed quick adsorption rate (only 10 min to reach equilibrium), high adsorption capacity and selectivity for REEs from water compared to other reported adsorbents. Maximum adsorption capacities of U6N@ZIF-8-20 for neodymium (Nd(III)), europium (Eu(III)), gadolinium (Gd(III)) and erbium (Er(III)) achieved to 249.90, 295.28, 316.22 and 340.95 mg g-1, respectively. U6N@ZIF-8-20 has superiority in selective adsorption of REEs from Cd(II), Zn(II), Cu(II), Mn(II) and Co(II) coexistence solution. The order of adsorption capacities for REEs is in agreement with the order of their electronegativity, ionic radius and charge density. Moreover, U6N@ZIF-8-20 showed better water stability and recyclability than single MOF. Overall, MOF@MOF hybrid material has efficiency in REEs separation from solutions, and has great advantage in the application of wastewater treating.

Ultrafast and facile microwave hydrothermal approach was applied to synthesize gallotannin modified carbon nanotube composites (CNT-GT) for effective recovery of Ga(III) from aqueous solutions. The successful preparation of CNT-GT composites was ascertained by a series of characterization techniques including TEM, FTIR, TGA, BET, Raman, XPS and Boehm titration. The CNT-GT obviously enhanced Ga(III) adsorption capability (170.8 mg g−1) as compared with the unmodified carboxylic carbon nanotubes (CNT-COOH). The CNT-GT composites had superior selectivity and excellent reusability. The adsorption mechanism of CNT-GT is based on the ion exchange of the surface hydroxyl hydrogen of CNT-GT with Ga(OH)2+, Ga(OH)2+, or Ga3+. In a word, the method described in this paper should be a quick and simple way to prepare highly efficient adsorbents, which has definite significance for the application of the environment.

In sulfuric acid medium, triisooctylamine was used as extractant to separate perrhenate from the aqueous phase. Molalites of perrhenate in the aqueous phase were measured from 278.15 K to 303.15 K at impurity ionic strength from 0.2 to 2.0 mol·kg–1. Standard extraction equilibrium constants K0 at different temperatures were calculated by polynomial approximation method. Some microcosmic property values in the process were investigated and obtained by Pitzer’s theory, which indicated enthalpy and entropy were both dominant thermodynamic factors.

In the present work, brown algae Laminaria japonica gel (CAG) was prepared by treatment with glutaraldehyde. The CAG gel has shown a low affinity for iron, copper, lead, nickel, manganese and zinc ions when the pH of solution is higher than 1.0, and the gel exhibited different adsorption behavior for Mo(VI) and Re(VII), which was difficult to separate each other. The adsorption equilibrium for Mo(VI) and Re(VII) on the CAG gel was best described by the Langmuir model and the maximum adsorption capacity for Mo(VI) and Re(VII) was evaluated as 65.90 mg g −1 and 38.19 mg g −1 , respectively. Adsorption mechanism, kinetic and thermodynamic study for the adsorption of CAG gel was discussed in detail. Moreover, reutilization of CAG gel was confirmed up to four adsorption–elution cycles in column-mode operation with no damage of gel, packed in the column. More important, the result provides a new approach for fractional recovery and separation of Mo(VI) and Re(VII) wastewater by using the CAG gel.

Perrhenate anion was extracted by extractant N1923 in sulfuric acid solution at ionic strength from (0.2 to 2.0) mol·kg–1. Molalities of perrhenate after extraction were measured in sulfuric acid aqueous system from (278.15 to 303.15) K. Standard extraction constants K0 were obtained by polynomial approximation method at various temperatures. Thermodynamic properties were investigated in the extraction process.

In this work, a novel di-2-ethylhexylamine modified magnetic chitosan (FCS-DIOA) was successfully synthesized and used to recovery Re(VII) in Mo–Re binary mixtures. The percentage content and the chemical structure of adsorbent were characterized by elemental analysis, gas sorption, magnetic properties, X-ray diffraction analysis, infrared spectroscopy, and Boehm titration, respectively. We discussed the effects of steric hindrance and basic strength of the secondary, the tertiary ammonium, or the quaternary ammonium gel on rhenium adsorption selectivity and capacity. More important, Re–Mo binary component separations on the FCS-DIOA gel consistently showed that the kinetic separation method exhibited a greater sorption capacity and selectivity (SelRe/Mo = 1.70–4.40). It was found that rhenium(VII) was adsorbed on the FCS-DIOA via charge-interactions and complexation by an infrared spectroscopy and X-ray photoelectron spectroscopy analysis. Relationships between adsorption mechanism and pH, adsorption iso...

With bi-continuous cubic mesostructures of Ia3d symmetry and interpenetrating cylindrical pore system, KIT-6 type mesoporous silica has attracted a great deal of interest for its application in various areas. Unfortunately, so far the reports on the tuning of mesostructures or other physical properties are rather limited due to the restrictions on synthetic conditions. In this work, one previously reported partitioned cooperative self-assembly (PCSA) process was applied for the synthesis of KIT-6s with good meso-orderings, allowing facile manipulation over mesostructures, e.g. the mesopore size, pore wall thickness and particle sizes. By simply partitioning the addition of tetraethoxysilane (TEOS), the mesopore sizes of KIT-6s can be varied between around 8 and 10 nm (KJS). For a given addition combination (1st part of 7.0 g and 2nd part of 3.0 g in total 10.0 g TEOS), the meso-orderings show some improvement with the increase in the interval time from 1 to 5 h. In combination with hydrothermal treatment at high temperatures (e.g. 140 °C), the PCSA process, though not yielding larger mesopore sizes, favors the formation of KIT-6 with higher meso-orderings than that of conventional method derived KIT-6. Moreover, the particle sizes of KIT-6s can be significantly reduced from sub-millimeter to several microns via the PCSA process. The PCSA process thus represents a simple but effective way to manipulate the mesostructures and particle sizes of KIT-6s.

Controlled synthesis of mesoporous silicas with tailorable mesostructures and particle morphologies has always been the research target of many materials scientists since the breakthrough in ordered mesoporous silicates in 1992, while the synthesis methodology is the key. Though standing out as a versatile and convenient approach, current non-ionic block copolymer (NBC) surfactant templating systems themselves in a broad sense polarize the two ‘extremes’: either being performed in far too diluted surfactant solution (DSS approach) or in much concentrated ones, i.e., liquid crystal phases (LCP approach). As a result, some limitations associated with each ‘extreme’ are also apparent: low silica content in synthesis mixture and therefore low synthesis efficiency and environmental unfriendliness mainly due to the high acid consumption for the DSS approach, while added synthesis complexity plus restricted functions for the LCP approach. Herein, we report a general, versatile and efficient synthetic approach, called water-deficient templating (WDT) system, bridging the above two ‘divided’ templating approaches based on the commonly used and commercially available NBCs, yet bearing some unusual characteristics in the templating manner that is different from those currently known. This approach to greater extent combines the advantages of both DSS and LCP approaches, enabling the facile engineering on the mesopore arrangements (wormhole-like, 2D-hexagonal or cubic), and effective adjustment in the mesopore sizes and facile tailoring in particle morphologies and even hierarchically macro–mesoporous monoliths. Moreover, significantly reduced synthesis volume and acid consumption in the WDT system re-assure that the NBC templated self-assembly process can be performed in this efficient and green way.

In the present study, crab shell chitin (CSC) has been used for the recovery of Mo(VI) from Cu/Fe containing solutions. The CSC gel showed a high affinity for Mo(VI) compared with other adsorbents, and the maximum adsorption capacity was evaluated as 252.27 mg g–1 in the case of pH 1, which could be explained by the structure of the CSC gel, containing more reactive −OH and/or −NH groups binding Mo(VI) ions. The experimental results fit satisfactorily to the Langmuir isotherm in comparison to the Freundlich, Temkin, and Dubinin–Radushkevich models. Biosorption kinetics data were successfully modeled using a nonlinear pseudo-second-order model. The sorption mechanism was investigated in detail through FTIR, EDS, and the percentage of positively charged amide analyses. Moreover, its excellent adsorption properties and applicability for Mo(VI) were demonstrated by the recovery and separation of Mo(VI) from Cu or/and Fe binary and ternary mixtures.

New adsorption gels were prepared by chemically immobilizing functional groups of ethylenediamine, diethylamine and/or triethylamine on orange waste, named OW-en, OW-DEA, and OW-TEA, respectively. By comparing with the adsorption of other coexisting metals, such as Re(VII), Pb(II), Fe(III), Zn(II), Mn(VII), Ca(II), and Cu(II), the novel gels exhibited selectivity only for Mo(VI) and the adsorption behavior obeys the Langmuir model. The maximum adsorption capacity for molybdenum was in the order, OW-en (2.17 mol/kg) > OW-TEA (1.26 mol/kg) > OW-DEA (0.88 mol/kg). A kinetic study for the adsorption of molybdenum at various temperatures confirmed that the endothermic adsorption process followed pseudo-second order kinetics. In addition, its excellent adsorption characteristics for Mo(VI) were confirmed by the adsorption and elution tests using a column packed with the OW-en gel, especially by separation of Mo(VI) from Mo-Re containing industrial effluent.

Based on the cheap sodium silicate and recently developed partitioned cooperative self-assembly (PCSA) process, this work demonstrated that the combination of the PCSA process with the hydrothermal treatment at elevated temperatures can produce the SBA-15s with large mesopores (>13 nm, KJS sizes), which noticeably larger than those prepared via the conventional method under the same synthetic conditions. Especially, the synthesis can be finished in a short period (24 h). The synthetic parameters, especially the amounts of precursor, interval times and stirring times, were all shown to have influence on the mesopore sizes.

Waste paper was chemically modified with dimethylamine (DMA) to obtain a tertiary-amine-type gel, named WPD. By comparing with the adsorption of other coexisting metals, such as Pb(II), Ca(II), Zn(II), Mn(VII), and Ni(II), this novel gel exhibited selectivity only for Mo(VI) and Re(VII) with a remarkably high capacity 4.99 mol·kg–1 and 0.96 mol·kg–1, respectively. The adsorption mechanism of Mo(VI) and Re(VII) on the WPD gel was proposed as the anion exchange process. In addition, both the adsorption behavior obeys the Langmuir model, and the endothermic adsorption process followed pseudosecond-order kinetics. Also, the effectiveness of recovery and separation of Mo(VI) and Re(VII) from industrial wastewater was also tested using a column packed with the WPD gel, and it showed highly encouraging results with respect to the stability of the gel and selectivity for the targeted metal ions in the presence of excess of other metal ions.

Equilibrium molalities of ReO4– were measured in the aqueous phase over the temperature range from (278.15 to 303.15) K, with NH4Cl as a supporting electrolyte at ionic strengths from (0.1 to 2.0) ...

In the solvent extraction system {R 3 N + NH 4 ReO 4 + n-C 7 H 16 + HCl + H 2 O}, the equilibrium molalities of ReO4 - were measured at ionic strength from (0.1 to 2.0) mol·kg -1 in the aqueous phase containing NH 4 CI as supporting electrolyte in the range of 278.15 K to 303.15 K. The standard extraction constants K 0 at various temperatures were obtained by methods of Debye-Huckel extrapolation and Pitzer polynomial approximation. Thermodynamic properties for the extraction process were calculated.

This work demonstrates that the combination of recently developed partitioned cooperative self-assembly (PCSA) process with the conventional mesopore swelling strategy can take the preparation of mesocellular foams (MCFs) one step further based on cheap sodium silicate precursor. Compared with conventional method derived MCFs, such synthesized MCFs show more uniform cell size distributions without using commonly employed additives, i.e., NH4F. Furthermore, when prepared with aging at 120 °C via the PCSA process, MCFs with large uniform cells (38.3 nm) and enlarged windows up to 7.9 nm can be obtained, resembling the conventional MCFs based on TEOS/P123/NH4F system. Moreover, a simple adjustment in the order of addition of trimethylbenzene in the PCSA process produces unique bimodal meso-mesoporous MCFs with ordered normal SBA-15 regions dispersed in the matrix.

A facile and versatile synthesis method, called the partitioned cooperative self-assembly process (PCSA process), is developed to prepare mesoporous SBA-15 silicas using P123 surfactant as template and cheap sodium silicate (SS) as silica precursor. It is demonstrated for the first time that by simply partitioning the cooperative self-assembly process, larger mesopore size (∼10 nm) can be achieved without using any additives or special synthetic conditions; high microporosities (>0.15 cm3 g−1) unprecendentedly persist upon hydrothermal treatment at 120 °C for 20 h with comparable mesopore sizes, which are in big contrast with those prepared by conventional method. The PHTS-type SBA-15s can also be favorably prepared by the PCSA process. In addition, the sizes of flower-like SBA-15 particle can be facilely tuned by adjusting the addition combinations of SS and interval time between the 1st and 2nd additions in the PCSA process. Interestingly, based on TEOS, the PCSA process yielded bimodal mesostructured SBA-15 with different wall thicknesses but the same mesopore size. The versatile PCSA process, which has shown its potential in tailoring the textural and morphological properties of SBA-15s, could lead to even wider spectrum of SBA-15s with various mesostructures if coupled with other synthetic measures.

It is for the first time demonstrated that the plugged hexagonal-templated silicas can be facilely and controllably prepared from cheap sodium silicate without using any additives. The formation of constricted/plugged mesostructures is attributed to the non-uniform/ill-templating behaviours between silicate oligomers and P123 molecules under the synthesis conditions employed.