Adsorption Activity Research Articles

Enhanced catalytic activity of Molar-like BaTiO3 by oxygen vacancies

Oxygen vacancies are found to have significant effects on the piezo-photocatalytic performance. For this reason, Molar-like and Bamboo-like BaTiO3 with the same tetragonal phase are synthesized by a two-step hydrothermal method. Molar-like BaTiO3 exhibits a superior piezo-photocatalytic performance by degrading the organic dye indigo carmine (IC), whose kinetic constant of 0.099 min−1 is 1.80 times higher than that of Bamboo-like BaTiO3. The same conclusion is drawn while the differences in specific surface areas are eliminated. There are more oxygen vacancies in Molar-like BaTiO3 compared to Bamboo-like BaTiO3, as shown in XPS results. The oxygen vacancies are favorable for light adsorption and O2 activation, thus an excellent photocatalytic performance is achieved. XRD refinements show that Molar-like BaTiO3 has a slightly higher content of piezoelectric tetragonal phase and stronger lattice distortion than Bamboo-like BaTiO3. However, the piezoelectric polarization of Molar-like BaTiO3 is weakened and the number of effective carriers is reduced due to more oxygen vacancies. The presented work provides a profound reference for the structural design of catalysts.

Acid-modified red mud biochar for the degradation of tetracycline: Synergistic effect of adsorption and nonradical activation

In this study, a novel acid-modified red mud biochar catalyst (MMBC) was synthesized by industrial waste red mud (RM) and peanut shell (PSL) to activate peroxodisulfate (PDS) for the degradation of TC. Meanwhile, MMBC exhibited remarkable adsorption capacity, reaching a 60% removal ratio of TC within 60 min (equilibrium adsorption capacity = 12 mg/g). After adding PDS, MMBC/PDS system achieved a 93.8% removal ratio of TC within 60 min. Quenching experiments and electron paramagnetic resonance (EPR) results showed that 1O2 played a dominant role in the degradation of TC and O2•− was the mainly precursor for the production of 1O2 in the MMBC/PDS system. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR) analysis showed that the surface Fe(II), –OH and –COOH provided the active sites for the activation of PDS by MMBC. In addition, acid modification optimised the surface structure of the catalyst and enhanced the conversion of Fe (mainly Fe(III) to Fe(II)), thereby improving the adsorption and catalytic efficiency of MMBC. This study confirmed that modified red mud biochar is an efficient composite with both adsorption and catalysis, providing new ideas for the practical treatment of antibiotic wastewater and the resource utilization of red mud.

Synthesis of a SiO2-MgO composite material derived from yellow phosphorus slag with excellent malachite green adsorption activity

There has been increasing attention devoted to the treatment of wastewater to eliminate organic dyes. Here, a composite material was developed using SiO2 matrix material obtained from yellow phosphorus slag and loaded with MgO, then examined for its ability to absorb the malachite green dye. The influence of a variety of variables, such as time, temperature, pH, and initial simulated effluent concentration, was investigated. These investigations demonstrated that when using this SiO2-MgO adsorbent, a maximum malachite green adsorption rate of 97.72 % was obtained, with precisely 115.64 mg g−1 of dye absorbed. Interestingly, the prepared SiO2-MgO was stable and regenerated successfully, exhibiting good performance throughout the four cycles. The specific surface area and pore size of the developed adsorbent composite material were found to be 352.76 m2 g−1 and 2–10 nm, respectively. Scanning electron microscopy, Fourier transform infrared spectrometry, X-ray diffraction, X-ray photoelectron spectroscopy, and Brunauer-Emmett-Teller analyses revealed that electrostatic adsorption, dipole-dipole H-bonding, ion exchange, and Yoshida H-bonding interactions were among the mechanisms used by this SiO2-MgO composite to adsorb malachite green. Importantly, this adsorbent can be simply and efficiently produced, making it well-suited to lowering MgO utilization and raising SiO2 adsorption efficacy while allowing for greater yellow phosphorus slag utilization and the establishment of a novel solid waste treatment approach.

Facile synthesis of MOF-derived N doped ZnO/C nanoparticles and its adsorption activity toward dye removal

Metal–organic framework (MOF)-derived materials have gained an increasing interest and showed potential adsorption features in numerous applications. Significant attempts have been performed to boost the structure, functionality, surface area and porosity in addition to adsorption performance of MOF-derived carbon nanoparticles. Here, nitrogen-doped ZnO/carbon nanoparticles were synthesized by directly pyrolysis of Zn based metal organic framework (ZIF-8) in a nitrogen atmosphere at two different temperatures (600 and 800 °C), followed by chemical impregnation with ZnCl2 solution with ratio (10:1) wt/wt, and thermal activation at 500 °C for 1 h. SEM, TEM, XPS, nitrogen adsorption–desorption method, and TGA characterization techniques were employed to investigate the morphology and structure characteristics. Then, thorough analysis of N doped ZnO/C-(600 and 800), adsorption capacity to remove Remazol brilliant blue reactive (RBBR) dye from aqueous phase was conducted. At room temperature, the porous N doped ZnO/C with high surface area attained a maximum adsorption capacity about 49.3 mg/g and demonstrated a strong adsorption capacity toward RBBR dye. The insights of kinetic, thermodynamic and adsorption isotherm studies of the as-demonstrated samples open up more discussion for MOFs-derived carbon adsorbents for wastewater treatment.

Influence of furnace atmospheres and potassium hydroxide activation on the properties of bamboo activated carbon and its adsorption towards 4-nitrophenol

Bamboo activated carbon (BAC) was synthesized as adsorbent for 4-NP adsorption due to its incredible adsorptive capability that has led it to its popularity. The effect of furnace atmospheres (argon, limited-air, vacuum), carbonizing temperatures (400–600 ℃), and activating temperatures (500–700 ℃) were investigated to achieve the largest surface area (SBET) of BAC. Its properties were analysed by using BET, FTIR, LVSEM, XRD, TGA, and Elemental analysis. The 4-NP adsorption was conducted by varying the pH (3−11), BAC dosages (0.05–0.4 g L-1), and 4-NP initial concentrations (10–100 mg L-1). Consequently, the argon-treated BAC (A67) had the highest SBET (1795.38 m2 g-1), stating that 600 ℃ of carbonizing temperature with 700 ℃ of argon flow activating temperature is the best condition to synthesize the BAC. The best adsorption efficiency (95.12%) was achieved by using A67 (pH 5, 0.2 g L-1, 50 mg L-1) with its maximum adsorption capacity (411.95 mg g-1). The Redlich-Peterson was the best-fitted isotherm model whereas the Pseudo-Second-Order (PSO) and Elovich were the best-fitted kinetic models for the 4-NP adsorption on BAC. The adsorption mechanism was analysed by applying the IPD model to the experimental data and was depicted in an insightful illustration. Overall, this research provides valuable insights into the adsorbent synthesis processes and highlights the importance of furnace atmospheres and KOH activation in tailoring the properties and adsorption activity of bamboo activated carbon adsorbents. The findings contribute to the development of sustainable and efficient adsorbent materials derived from renewable resources, with significant implications for environmental remediation and waste treatment applications.

Inhibiting effect of C3H6 on the performance of Cu-SSZ-13 catalysts for NH3 selective catalytic reduction

Hydrocarbons (HCs) have been found to be a potential source of catalyst poisoning in ammonia selective catalytic reduction (NH3-SCR) of NOx. As one of the predominant constituents of hydrocarbons, propene (C3H6) was selected to investigate its inhibitory effect on Cu-SSZ-13 catalysts utilized in the NH3-SCR reaction. The results of standard SCR tests mixing C3H6 and NH3 showed that the NH3-SCR activity of Cu-SSZ-13 catalysts was inhibited in the range of 150–650 °C with the introduction of C3H6 and the NOx conversion was lowest in the presence of 2000 ppm C3H6. The competitive adsorption and NH3 oxidation activity were extensively studied. It was found that NH3 and C3H6 could both be stored on Brønsted acid sites and Cu sites. The introduction of C3H6 during NH3-TPD experiments caused an increase of weakly adsorbed NH3 on the weak Lewis acid sites and a decrease of adsorbed NH3 on the strong Lewis acid sites and Brønsted acid sites, confirming the existence of the competitive adsorption between NH3 and C3H6. Based on TPO experiments, C3H6 enhanced the NH3 oxidation activities in the temperature range of 250–650 °C, and coke deposition might be generated on the catalysts, causing the decline of NOx conversion during NH3-SCR with C3H6.

Ultra-fast adsorption of radioactive technetium (99mTc) by using mining waste clay samples, Abu-Tartur, Egypt

In this study, we have opened a great route to fabricate a high-performance nanocomposite for various functional applications based on the composite of a natural stone. A clay sample (black shale (B.Sh)) was collected from the Abu-Tartur area in Egypt. The black shale was organically modified with organic materials in our laboratory, which is called organo-black shale (O-B.Sh). The samples were characterized by XRD, FTIR, SEM, and XRF. These techniques confirmed that the samples have multi-oxide phases with approximately SiO2 at 54.1%, Al2O3 at 24.73%, Fe2O3 at 6.02%, K2O at 1.12%, MgO at 1.09%, and Na2O of 0.09%, as calculated by XRF. The two samples were applied to the adsorption processes of the radioactive technetium materials, which have been used for the medical treatment of the cancer institute of Upper Egypt. The adsorption processes were performed at various concentrations of the radioactive material and various amounts of clay samples. The as-collected B.Sh sample showed an adsorption activity of 65%, however, the organically modified materials showed a high adsorption rate toward technetium reaches to 100% in a very short time and without any further process. The present collected materials are very promising to withdraw the radioactive materials from the saline solution to save human and environmental health. We believe these multi-compound composites may open a new approach for creating new fabric composites with high performance for various applications.

Directional Shunting of Photogenerated Carriers in POM@MOF for Promoting Nitrogen Adsorption and Oxidation.

The efficient catalysis of nitrogen (N2 ) into high-value N-containing products plays a crucial role in the N economic cycle. However, weak N2 adsorption and invalid N2 activation remain two major bottlenecks in rate-determining steps, leading to low N2 fixation performance. Herein, an effective dual active sites photocatalyst of polyoxometalates (POMs)-based metal-organic frameworks (MOFs) is highlighted via altering coordination microenvironment and inducing directional shunting of photogenerated carriers to facilitate N2 /catalyst interaction and enhance oxidation performance. MOFs create more open unsaturated metal cluster sites with unoccupied d orbital possessing Lewis acidity to accept electrons from the 3σg bonding orbital of N2 for storage by combining with POMs to replace bidentate linkers. POMs act as electron sponges donating electrons to MOFs, while the holes directional flow to POMs. The hole-rich POMs with strong oxidation capacity are easily involved in oxidizing adsorbed N2 . Taking UiO-66 (C48 H28 O32 Zr6 ) and Mo72 Fe30 ([Mo72 Fe30 O252 (CH3 COO)12 {Mo2 O7 (H2 O)}2 {H2 Mo2 O8 (H2 O)}(H2 O)91 ]·150H2 O) as an example, Mo72 Fe30 @UiO-66 shows twofold enhanced adsorption of N2 (250.5cm3 g-1 ) than UiO-66 (122.9cm3 g-1 ) at P/P0 =1. And, the HNO3 yield of Mo72 Fe30 @UiO-66 is 702.4µgg-1 h-1 , ≈7times and 24 times higher than UiO-66 and Mo72 Fe30 . This work provides reliable value for the storage and relaying artificial N2 fixation.

PMS activation by hollow sulfur doped multilayer carbon shell wrapped CoFe alloy: Confined adsorption and surface activation

Confined catalysis is an effective strategy to deal with the low utilization of active sites and poor cyclic stability in metal catalysts. However, the impact of confinement effect on the catalytic degradation process of organic pollutants is unclear. A hollow sulfur doped multilayer carbon shell wrapped cobalt iron alloy catalyst (CoFe@CS) is designed here to activate peroxymonosulfate (PMS) for bisphenol A (BPA) degradation. The hollow porous multilayer carbon shell provides a confined space for the rapid interface adsorption of PMS and in-situ degradation of BPA, which contribute to the superior BPA removal rate of nearly 100% within 20 min. Moreover, confinement catalysis favors the anti-interference ability to cope with changes in solution conditions like pH, organic matter, inorganic anions, etc., which favors the application in realistic wastewater. X-ray photoelectron spectroscopy (XPS) results demonstrate that the crucial Co2+ sites are regenerated by sulfur reduction, ensuring the sustainable use. Electrochemical analysis and density functional theory (DFT) calculations reveal that S doping improves the electron transfer capability and chemical reactivity of CoFe@CS, which drives direct oxidation as the dominant pathway for BPA degradation. The CoFe@CS/PMS system could efficiently mineralize BPA (up to 87.74%) and reduce residual toxicity. This work not only provides a reference for the design of efficient and stable transition metal catalysts but also offers a new insight into the confined degradation research of BPA in advanced oxidation technologies.

Study on adsorption behaviors of different cresols: First-principles calculation

Removal of organic pollutants is an important issue of wastewater treatment. The adsorption effects of different types and numbers of O-cresol(ortho-cresol), M−cresol(meta-cresol) and P-cresol(para-cresol) on Au(111) surface were studied by first-principles calculation based on density functional theory(DFT). Results show that Au(111) surface has different adsorption activities for different cresols. When adsorption occurs, the aromatic ring, hydroxyl group and methyl group in the aromatic ring of cresol molecules in different systems showed different tilt angles. When a single cresol molecule is adsorbed, the aromatic ring plane consists of carbon and hydrogen atoms is basically parallel to the outermost layer plane of Au(111). With increasing number of same cresol molecules, the tilt degree between the aromatic ring of two M−cresol molecules and Au(111) surface is greater. However, when the number of cresol molecules is 3, C–H bond in methyl group and H-O bond of cresol molecules that close to each other in M−cresol adsorption system are significantly elongated. At the same time, the angle between the aromatic ring plane and Au(111) surface changes greatly. For the adsorption of three types of cresol molecules, the tilt angle order of aromatic ring in cresol molecules is P-cresol > O-cresol > M−cresol. From the comprehensive analyses of adsorption configuration, adsorption energy, adsorption distance and charge transfer, it can be seen that the adsorption priority of same cresol molecule on Au(111) surface is O-cresol > P-cresol > M−cresol. For the co-adsorption of cresol molecules, the adsorption process of 1O-1 M−1P system tends to preferentially occur on Au(111) surface. This study provides theoretical guide for the design of adsorbent materials for efficient removal of organic pollutants from wastewater.

Preparation of Bamboo-Based Activated Carbon via Steam Activation for Efficient Methylene Blue Dye Adsorption: Modeling and Mechanism Studies.

Dye pollution has long been an ecological and human health issue. Activated carbon is considered to be the most promising material for dye adsorption. In this study, bamboo was used as a biomass precursor to produce activated carbon with a high specific surface area by the steam activation method. The physical activation reaction between water vapor and bamboo promotes the carbonization product to have a rich porous structure. The prepared activated carbon was investigated from the perspectives of surface morphology, elemental change, surface porosity, and surface functional groups using a variety of techniques. According to the Brunauer-Emmett-Teller analysis, the activated carbon has a high surface area (1273 m2/g) and a mesoporous structure (average pore size 3.1 nm). On this basis, the effect of activated carbon on the removal of methylene blue (MB) dye from aqueous environments was evaluated and optimized by response surface methodology (RSM). Key adsorption parameters include initial MB concentration (150-200 mg/L), adsorption time (5-120 min), adsorbent dosage (30-50 mg), adsorption temperature (5-50 °C), and solution pH (3-11). Box-Behnken design (BBD) was used for modeling and analysis. Kinetic and isotherm model studies show that pseudo-second-order model kinetics and Langmuir isotherm can better describe the process of MB dye adsorption. This study will provide new ideas for the preparation of bamboo-activated carbon and provide a model prediction basis for dye adsorption research.

Surface activity, kinetics, thermodynamics and comparative study of adsorption of selected cationic and anionic dyes onto H3PO4-functionalized bagasse from aqueous stream.

The discharge of dyes into the water body creates toxicity to aquatic organisms because of their aromatic structure and difficult degradation. So, the treatment of dye-contaminated wastewater is required before releasing it. In the present study, thermally treated (600 °C) and H3PO4 (55%)-functionalized bagasse, henceforth called thermochemically activated bagasse (TCAB), was synthesized as potential adsorbent for the effective removal of selected cationic and anionic dyes from their aqueous stream. TCAB characterization was done employing FT-IR, SEM, XRD, zeta potential, BET, and PZC techniques. The comparative study shows that the relative adsorption on TCAB followed the sequence, methyl red (185 mg/g) > safranin (178 mg/g) > congo red (146 mg/g) > brilliant green (139 mg/g) > malachite green (130 mg/g) > bromocresol green (94 mg/g). The adsorption efficiency was investigated concerning the effect of change in TCAB dose (0.05-0.3 g/100 mL), initial dye concentration (20-200 mg/L), pH (4.0-10.0), ionic strength (0.1-0.5 M KCl), urea concentration (0.1-0.5 M) and temperature (25-45 °C). The representative adsorption isotherms belong to typical L-type. The time-dependent dye removal was best explained by the pseudo-second-order (PSO) kinetic model (R2 = 0.9859-0.9991), while equilibrium data were best explained by the Freundlich model (R2 = 0.9881-0.9961). Thermodynamic study showed the spontaneous (ΔG0 <0) and exothermic nature (ΔH0 <0) of the adsorption of different cationic and anionic dyes. The cyclic adsorption ability of TCAB for different dyes was checked up to three cycles (185 to 168 mg/L for MR, 178 to 165 mg/L for SF, 146 to 130 mg/L for CR, 139 to 127 mg/L for BG, 130 to 114 mg/L for MG and 94 to 80 mg/L for BCG), and no significant decrease in the adsorption capacity was noticed. So, the present study provides valuable insights into the adsorption of cationic and anionic dyes onto H3PO4-functionalized bagasse. Addressing the adsorptive aspects enhances the clarity, reliability and applicability of the study's findings and contributes to its overall scientific impact.

Efficient removal of piroxicam and ketoprofen by acid-modulated iron(III) metal–organic frameworks

Pharmaceutical substances such as piroxicam and ketoprofen have been detected in worldwide water sources, posing an emerging risk to environmental health. Therefore, developing a low-energy and efficient method to remove these pollutants from the environment is necessary. Herein, the adsorption of piroxicam and ketoprofen from water has been investigated by using a series of modulated metal–organic frameworks, namely MIL-126 synthesized in the presence of various amounts of acetic acid. The material synthesized with 1 equivalent of the acid modulator, MIL-126-1AA, has been found to show impressive adsorption activities, irrespective of its lower surface area than the other MOF samples studied. MIL-126-1AA exhibits maximum adsorption capacities of 209.65 mg g−1 for piroxicam and 452.49 mg g−1 for ketoprofen, respectively. Such high adsorption capacities can be attributed to the permanent porosity of MIL-126, an optimal amount of defects, as well as a delicate balance of non-covalent interactions between the MOFs and the adsorbates, as revealed from the adsorption studies and X-ray photoelectron spectroscopic analysis. Additionally, the durability of the adsorbents allows them to be reusable after multiple cycles without significant decrease in the adsorptive performance, further highlighting their potentials for the remediation of pharmaceuticals and other organic pollutants from the environment.

Selective uptake and removal of aromatic and heterocyclic compounds by para-dicyanobenzene-linked, EFe3(CO)9-incorporated (E = Te, Se), semiconducting Cu chain polymers

The uptake and removal of volatile and toxic organic compounds is an important issue in modern industrial chemistry because these organic pollutants have long-term effects on public health and the global environment. In this work, we successfully synthesized two novel para-dicyanobenzene (p-DCB)-linked, EFe3(CO)9-incorporated (E = Te, Se) 1D polymers [EFe3(CO)9Cu2(p-DCB)1.5]n (E = Te, 1a; Se, 1b) from liquid-assisted grinding (LAG) of the di-Cu compounds [EFe3(CO)9Cu2(MeCN)2] with p-DCB. Polymers 1a and 1b had isomorphous structures with single- and double-p-DCB linkers alternatively connected to Cu atoms of EFe3(CO)9Cu2 (E = Te, Se) cores, in which two p-DCB of the double-p-DCB moiety were parallel-displaced with the π···π interaction on their benzene rings. The selective adsorption of C7−C10-alkyl aromatics, polycyclic aromatics, and heterocyclic compounds by 1a and 1b was accomplished via neat grinding or THF-aided LAG processes. These reactions led to the formation of the guest molecule (G)-intercalated products, i.e., 1a- and 1b-based polymers [EFe3(CO)9Cu2(p-DCB)1.5·(G)m]n [E = Te, 1a·mG; E = Se, 1b·mG; m = 0.5 or 1] and the THF-introduced single-p-DCB-bridged polymer [TeFe3(CO)9Cu2(p-DCB)·(THF)]n (2a·1THF). These adsorption activities of 1a and 1b were thoroughly evaluated by single-crystal and powder X-ray analysis and TGA and DSC measurement, where some C−H···π, π···π, and C−H···E (E = O, S) interactions between guest molecules and the p-DCB linkers were observed to stabilize polymer chains. The desorption of volatile heterocyclic (THF, furan, thiophene) or alkyl aromatic (toluene, m-xylene, mesitylene, durene) guest molecules to give the parent polymers 1a and 1b could be achieved by vacuum and recrystallization or stepwise LAG process in the Te system. Importantly, these EFe3(CO)9Cu2-incorporated (E = Te, Se) polymers 1a and 1b, as well as their host−guest adducts, exhibited semiconducting behaviors possessing tunable energy gaps (1.36−1.51 eV) with moderate electrical conductivities ((1.21−6.55)×10–7 S·cm–1), in which the guest molecules played a crucial role in modulating the electron transport in the solid state.

Activated carbon with high mesopore ratio derived from waste Zanthoxylum bungeanum branches by KNO3-assisted H3PO4 staged activation for toluene adsorption.

Waste Zanthoxylum bungeanum branches were used to prepare activated carbon adsorbents with high mesopore ratio by H3PO4 staged activation method with adding KNO3 additive. The prepared activated carbon adsorbents were characterized by SEM, BET, FT-IR, and XRD. The adsorption properties of the prepared activated carbon adsorbents were evaluated by the toluene adsorption/desorption in air. The quasi-first-order, quasi-second-order, and Bangham models were used to fit the obtained toluene adsorption results. The oxidative etching of KNO3 additive improved the pore-forming ability of the H3PO4 activator to enhance the activation pore-forming effects of the selected biomass raw material. The secondary pore-forming effects of K atoms promoted the effective expansion of the pore diameter in the activated carbon preparation process to prepare activated carbon adsorbents with high mesopore proportion. The specific surface area and mesopore proportion of the activated carbon adsorbents prepared by adding KNO3 additive exceeded 1100 m2/g and 71.00%, respectively, and the toluene adsorption capacity exceeded 370.00 mg/g. The rich mesopore structures can effectively reduce the toluene mass transfer resistance, which can promote the corresponding activated carbon adsorbent to be regenerated by low-temperature (40 °C) thermal desorption. The toluene adsorption on the prepared activated carbon adsorbents includes surface adsorption and diffusion in pore structures, and the toluene adsorption mechanism is more consistent with the Bangham kinetic model.

Modulating the Reaction Configuration by Breaking the Structural Symmetry of Active Sites for Efficient Photocatalytic Reduction of Low-concentration CO2.

Photocatalytic conversion of low-concentration CO2 is considered as a promising way to simultaneously mitigate the environmental and energy issues. However, the weak CO2 adsorption and tough CO2 activation process seriously compromise the CO production, due to the chemical inertness of CO2 molecule and the formed fragile metal-C/O bond. Herein, we designed and fabricated oxygen vacancy contained Co3O4 hollow nanoparticles on ordered macroporous N-doped carbon framework (Vo-HCo3O4/OMNC) towards photoreduction of low-concentration CO2. In-situ spectra and ab initio molecular dynamics simulations reveal that the constructed oxygen vacancy is able to break the local structural symmetry of Co-O-Co sites. The formation of asymmetric active site switches the CO2 configuration from a single-site linear model to a multiple-sites bending one with a highly stable configuration, enhancing the binding and structural polarization of CO2 molecules. As a result, Vo-HCo3O4/OMNC shows unprecedent activity in the photocatalytic conversion of low-concentration CO2 (10% CO2/Ar) under laboratory light source or even natural sunlight, affording a syngas yield of 337.8 or 95.2 mmol g-1 h-1, respectively, with an apparent quantum yield up to 4.2%.

Modulating the Reaction Configuration by Breaking the Structural Symmetry of Active Sites for Efficient Photocatalytic Reduction of Low‐concentration CO2

AbstractPhotocatalytic conversion of low‐concentration CO2 is considered as a promising way to simultaneously mitigate the environmental and energy issues. However, the weak CO2 adsorption and tough CO2 activation process seriously compromise the CO production, due to the chemical inertness of CO2 molecule and the formed fragile metal‐C/O bond. Herein, we designed and fabricated oxygen vacancy contained Co3O4 hollow nanoparticles on ordered macroporous N‐doped carbon framework (Vo−HCo3O4/OMNC) towards photoreduction of low‐concentration CO2. In situ spectra and ab initio molecular dynamics simulations reveal that the constructed oxygen vacancy is able to break the local structural symmetry of Co−O−Co sites. The formation of asymmetric active site switches the CO2 configuration from a single‐site linear model to a multiple‐sites bending one with a highly stable configuration, enhancing the binding and structural polarization of CO2 molecules. As a result, Vo−HCo3O4/OMNC shows unprecedent activity in the photocatalytic conversion of low‐concentration CO2 (10 % CO2/Ar) under laboratory light source or even natural sunlight, affording a syngas yield of 337.8 or 95.2 mmol g−1 h−1, respectively, with an apparent quantum yield up to 4.2 %.

Mechanistic investigation of mesoporous Mg2+ doped CeO2 encapsulated Fe3O4 core-shells for the selective adsorptive removal of malachite green

Economically viable, easy to operate and highly efficient techniques for water treatment are one of the basic amenities that should be provided to every individual in our society. Here we have developed Fe3O4@Mg2+ doped CeO2 core-shells by a co-precipitation route as magnetically retrievable adsorbents which are highly selective towards hazardous malachite green. The developed core-shell nanostructures were well-characterised using XRD, FE SEM, HR TEM, XPS, BET, VSM and TGA. The developed Fe@CMg-1:2 core-shells exhibited a removal efficiency of 95.1% towards Malachite green. Various parameters affecting the adsorption activity were investigated in detail. The nature, extent and mechanism of the adsorption were evaluated using various adsorption isotherm and kinetic models. Dubinin-Radushkevich (D-R), Freundlich and Temkin adsorption models were used to fit the isotherm data and the maximum adsorption capacity (qm) was found to be 18.44 mg g−1 according to Dubinin-Radushkevich (D-R) model. It was found that the selective adsorption of malachite green over Fe@CMg-1:2 core-shells follows heterogeneous multilayer adsorption which obeys pseudo-second-order kinetics. The developed Fe@CMg-1:2 core-shells also exhibited high thermal stability and reusability. Fe@CMg-1:2 core-shells retained 82.4% removal efficiency even after four successive reusability cycles. Easy separation, high selectivity and cost-effectiveness are the highlights of the developed mesoporous Mg2+ doped CeO2 encapsulated Fe3O4 core-shell structures.

Adsorption of heavy metals and antibacterial activity of silicon-doped chitosan composite microspheres loaded with ZIF-8

A bifunctional composite microsphere adsorbent with high adsorption and antimicrobial activity was synthesized by combining zeolite imidazolate framework (ZIF-8) chitosan microspheres doped with silica (CS/DS) prepared by electrospraying method for removing heavy metal ions Pb2+ and Cu2+. The samples were characterized by chemical, morphological, thermal behavior, specific surface area and pore size analysis. Compared with chitosan microspheres and CS/DS, CS/DS@ZIF-8 has good crystallinity, high specific surface area, multi-pore size distribution, better thermal stability and more active groups. The adsorption process of Pb2+ and Cu2+ on CS/DS@ZIF-8 conformed to the Langmuir model and Pseudo 2nd kinetics model, of which the maximum adsorption capacities were 340.94 mg/g and 308.27 mg/g, respectively, which were better than those of CS and CS/DS microsphere adsorbents. At the same time, the composite microspheres have excellent antibacterial properties and have application potential in solving practical wastewater treatment. It is worth mentioning that CS/DS@ZIF-8 maintains 81.3 % and 72.9 % adsorption rates for Pb2+ and Cu2+ after five cycles. This study aims to help design new bifunctional adsorbents with the ability to remove chemical and biological pollutants to promote practical application scenarios.

Use of Various UVC Photofunctionalization Times to Modify Surface Characteristics and Enhance the Biologic Activity of SLA Titanium.

To evaluate the effect of ultraviolet-C light (UVC) photofunctionalization treatment time on the biologic activity of airborne particle-abraded and acid-etched (SLA) titanium surfaces and to analyze its physical and chemical mechanisms. SLA titanium was treated with UVC light for different lengths of time (10 minutes, 20 minutes, 30 minutes, 1 hour, 2 hours, 4 hours, and 24 hours), and then changes to its surface characteristics were evaluated via electron microscope scanning, X-ray photoelectron spectroscopy (XPS), water contact angle measurement, and zeta potential measurement. The effect of UVC photofunctionalization on the biologic processes of SLA titanium surfaces was assessed by analyzing the bovine serum albumin adsorption, adhesion, proliferation, morphology, and alkaline phosphatase activity of MG-63 cells. UVC irradiation did not change the topography of SLA titanium surfaces. As treatment times increased, the water contact angle decreased from 120 degrees to 0 degrees, and the hydrocarbon content decreased. Zeta potential testing showed increased surface potential of photofunctionalized titanium. In vitro testing showed that cell adhesion, proliferation, morphology, and alkaline phosphate (ALP) activity on titanium surfaces were significantly improved by UVC photofunctionalization. UVC photofunctionalization can improve the biologic activity of SLA titanium surfaces by removing hydrocarbons and increasing the surface potential of titanium.