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Constructing robust adsorbents for SO2 removal remains a challenging issue. Herein, a U-Co bimetallic-organic framework, namely, ECUT-123, showing a helical 1D pore decorated by abundant -CH3 groups, enables ultrahigh stability under acid, base, and water. This merit further supports its big potential for the removal of trace SO2.

Dyes, a kind of visible chemical, have severe deleterious effects on human health and ecological environment. In this work, batch biosorption experiments were carried out under various experimental conditions such as pH value and agitation time to optimize the potentiality of Enteromorpha prolifera for the removal of malachite green (MG) dye from aqueous solution (70·7%). Then, the algal biomass was treated with a dielectric barrier discharge (DBD) in helium for 4 and 10 min to enhance MG removal efficiency (84·7 and 96·6%). In addition, Fourier-transform infrared spectroscopy in combination with scanning electron microscopy was employed to monitor the chemical and physical changes of algal cells treated by DBD. This study illustrates that DBD may serve as an effective tool to activate the functional groups on the cell wall surface for dye binding, and it even offers an alternative new technique to improve the adsorption properties of native biosorbents for the removal of toxic dyes from wastewater.

The reticular chemistry strategy presents a powerful molecule-design tool to tailor the physical and chemical properties of metal-organic framework (MOF). In this work, we for the first time investigated the effect of organic ligands on the radionuclide sequestration (TcO4−) of thorium-organic framework. Through a coordination modulation technique, two novel isoreticular thorium-organic frameworks, namely Th-MOF-67 and Th-MOF-68, were obtained. Relative to the antetype MOF of Th-MOF-66 that shows extremely low uptake of ReO4− (a chemical surrogate of radioactive TcO4−), the isoreticular MOFs of Th-MOF-67 and Th-MOF-68 enable ultrahigh uptake of ReO4−, giving an impressively 36.8-fold or 56-fold enhancement, respectively. The adsorption capacity of Th-MOF-68 is as high as 560 mg/g, exceeding most reported adsorbents for such use. The mechanism for such exceptional outstanding performance, as unveiled by both the single crystal X-ray diffraction and theoretical calculation, is due to coordination interaction for Th-MOF-67, when a tetrazolate ligand was used, or a combined effect from both coordination interaction and anion-exchange for Th-MOF-68, if using a triazolate ligand.

A novel extraction method of volatile aroma compounds (VACs) from walnut oil (WO) using monolithic material adsorption extraction (MMSE) was developed herein, and its efficiency was compared with the conventional extraction method based on solid-phase microextraction (SPME) combined with gas chromatography-olfactory-mass spectrometry (GC-O-MS). After protocol optimization of MMSE-RSC18, 77 volatile compounds (38 ones can be sniffed) were extracted from WO, thus having a better performance compared to SPME (56 volatile compounds, 35 ones can be sniffed). Subsequently, based on flavor dilution factors (FDs), odor activity values (OAVs), and recombination and omission experiments, key aroma-active compounds in WO were 1-octen-3-ol (OAV = 82.58), (E)-2-decenal (OAV = 4.10), linalool (OAV = 2.37), γ-dodecalactone (OAV = 2.30), 2-pentylfuran (OAV = 1.62), (E)-2-nonenal (OAV = 1.14) and pentanal (OAV = 1.04). Collectively, compared to HS-SPME, MMSE-RSC18 provided higher capture efficiency of VACs, enabling efficient extraction and analysis of sample aromas.

The morphologies of CuO/CeO2-ZrO2 catalysts were successfully controlled by simply changing the synthesis temperature using hydrothermal method. The catalytic performance for toluene oxidation was correlated with the characterization results of HRTEM, BET, XRD, H2-TPR, Raman, and O2-TPD. It was found that toluene can be oxidized into CO2 and H2O completely over the obtained catalysts, and the rod-like Cu/Ce-Zr-100 exhibits the best activity and CO2 selectivity. The rod-like CeO2-ZrO2 supports preferentially exposes (110) and (100) crystal planes of CeO2, which provides more oxygen vacancies and stronger interaction between CuO and the support in Cu/Ce-Zr-100. And the strong synergetic effect in Cu/Ce-Zr-100 promotes the dispersion of CuO on the support surface, leading to the enhancement of reducibility, oxygen vacancy concentration, adsorption and activation of gaseous oxygen, which are responsible for the good catalytic performance of toluene oxidation.

In this work, chabazite SSZ-13 samples with different cations were synthesised by hydrothermal method and thoroughly analysed using various characterisation techniques. The role of types of cations in CO2 and CO adsorption measurements was investigated. The adsorption isotherms were fitted by Langmuir, Langmuir-Freundlich and Toth adsorption models, respectively. The result shows that the Langmuir-Freundlich model is the most suitable for the adsorption isotherms of SSZ-13 molecular sieves. The adsorption isotherms of the fitted CO2 and CO were analysed to study the high silicon SSZ-13 samples of alkali metal cations Li+, Na+, K+ and Cs+ for ion exchange. The result shows that Na+ has the highest adsorption capacity, but the adsorption selectivity is extremely low. K+ has the lowest adsorption capacity, but it has excellent adsorption selectivity, which may be attributed to its large cation radius and the special position of cations in CHA skeleton structure, resulting in the formation of ‘molecular trapdoor’ effect. In addition, Cs+ has a larger ionic radius than K+, but the adsorption selectivity is not significantly improved, similar to Li+. It can be determined that the ‘molecular trapdoor’ effect has a significant relationship with the position of cations in the framework.

In the research, N-doped cost-effective carbon dioxide adsorbents with ultrahigh selectivity are prepared using waste walnut shell pyrolysis by two-step activation and urea modification. The carbonaceous adsorbent exhibits excellent pore structure due to the catalytic degradation of H3PO4 and the etching action of KOH. The optimized sample, HAC-850-1.5, shows high CO2 adsorption 5.13 mmol/g at 0 °C. The study also indicates that nitrogen content, Vm/Vt, and porous texture characteristics play indispensable parts in impacting the CO2 adsorption of these prepared N-doped porous materials under atmospheric pressure. Furthermore, prepared carbonaceous adsorbents possess other superiorities including reasonable Qst and good recyclability and stability. It should not be overlooked that the adsorbent has a selectivity of more than 800 for CO2/N2 at low pressure, which is highly promising in CO2 adsorption through flue gas when contrasted with diverse solid adsorbents.

Various techniques have been utilized in experiments to evaluate the performance of photocatalysts and to understand the corresponding catalytic mechanism. However, it is still challenging to demonstrate the phenomenon in detail during the catalytic process in experiments to fundamentally understand the catalytic mechanism. Density function theory (DFT) is an excellent technique to solve this problem at the level of electrons and atoms. However, the evaluation procedure for photocatalysts based on DFT calculations was unclear. Thus, in this work, we propose an evaluation procedure for photocatalysts for the degradation of volatile organic compounds (VOCs) from the point of view of DFT calculations through the following aspects: (i) the band structure of photocatalysts, including the band gap, capability of photoadsorption and the positions of the conduction band (CB) and valence band (VB); (ii) the adsorption of H2O, O2 or other oxidants; (iii) the adsorption of pollutants; (iv) the reaction pathway for pollutant degradation. To demonstrate the application of the proposed evaluation procedure, g-C3N4 dots/graphene is taken as an example to evaluate its photocatalytic performance. The results show that g-C3N4 dots/graphene has enhanced visible light absorption with significantly reduced height for photoelectron excitation and the photoelectron migrates between the parts of the heterostructure, from the valence band of the g-C3N4 dots to the graphene layer, and then to the conduction band of the g-C3N4 dots, which promotes light adsorption and induces the generation of electron–hole pairs with a low recombination rate. In addition, both the adsorbed H2O and O2 have strong interactions with g-C3N4 dots/graphene, inducing activation to form ˙OH and ˙O2− radicals to attack and degrade the adsorbed VOCs. Therefore, a procedure to evaluate the performance of photocatalysts for VOCs degradation based on DFT calculations is proposed in this work, and the evaluation procedure is successfully applied to predict the high photocatalytic performance of g-C3N4 dots/graphene, where a unique photoelectron excitation pathway is also demonstrated within the heterostructure.

The dry reforming of methane (DRM) over Ni-MSC catalysts promoted by different Ce/Ca ratios was compared. The different Ce/Ca ratios proportions were introduced by coprecipitation. The catalysts with different content of promoter were characterized by N2 adsorption, XRD, H2-TPR and TEM. XRD and TEM results demonstrated that Ni–4Ce1Ca-MSC catalyst modified with high Ce/Ca had the best dispersibility and the smallest Ni particle size, resulting in more surface active sites. The synergy between Ce and Ca made a great contribution to prohibiting the generation of carbon deposits and the sintering of active metal during DRM procession. In contrast, catalysts modified only with Ca or Ce exhibited poor catalytic performance, resulting in significant deposition of carbon on the surface of the Ni–5Ca-MSC catalyst. In addition, the high Ce concentration greatly increases the oxygen storage capacity, which helps to form oxygen vacancies by mutual conversion of Ce4+/Ce3+ and Ni2+/Ni0.

Amine loaded solid adsorbents are promising for the post-combustion CO2 capture. A current challenge is how to synthesize support with excellent pore structure by cost-effective methods as supports for amine loading. Herein, hierarchical bimodal mesoporous silica (HMS) was synthesized by using P123 as template through the partitioned cooperative self-assembly process. The prepared HMS is found to have large pore volumes and hierarchical pore networks. Subsequently, a series of tetraethylenepent amine (TEPA) functionalized adsorbents is prepared and CO2 capture measurements were implemented in a fixed-bed reactor to investigate the effects of TEPA loading and mesoporous structure. And the influence of CO2 concentration on capture performance was also studied in both In-situ DRIFTS and adsorption kinetic ways. The results show that the CO2 capture amount of HMS is up to 5.82 mmol/g at 70 wt.% TEPA loading and 75 ℃ with 15 vol% CO2. The large pore volumes significantly increase the amine loading and the interconnected hierarchical mesopores networks facilitated the dispersion of amine. The higher CO2 concentrations is conducive to the formation of carbamic acid and the decrease of CO2 adsorption activation energy, thereby facilitating the CO2 adsorption. In addition, poly (propylene glycol) bis (2-aminopropyl ether) (PEA) was also introduced in the adsorbent to further improve the adsorption performance. The results show that the introduction of PEA can offer increased CO2 capture amount, improved thermal stability and regenerability due to the participation of the ether group in the reaction of CO2 with the amine group and improved the thermal stability of the TEPA and PEA co- functionalized adsorbent.

Organic films were widely found on indoor impermeable surfaces exposed to gaseous organic compounds, but few studies have addressed the film growth details on different indoor substrates. In this study, we observed the topography evolution of phthalic acid ester (PAE) organic films on three impermeable substrates: polished glass (G-P), mirror-polished stainless steel (SS-M) and drawn stainless steel (SS-D). PAE organic films were preferentially formed upon the flat surface with sparse inherent nano-peaks of substrate G-P and in valleys of substrate SS-M and SS-D. Surface uniformity of substrates and viscosity of PAE molecules were inferred as critical parameters determining the surface average adhesion forces. We obtained the partition coefficients of DEP, DnBP, BBP and DEHP on substrate G-P, SS-M and SS-D by fitting the initial monolayer adsorption process. Organic films continuously grew instead of reaching adsorption equilibrium after long-term PAE exposure, indicating that multilayer adsorption may occur. The organic film growth rates in saturated gas-phase PAE concentrations were quantified as about one-tenth of the results in previous studies where substrates were simultaneously exposed to multiple pollutants. To sum up, the results outline PAE adsorption details on impermeable materials and provide a reference for better estimation on PAE exposure assessment.

This study offers a simple, environmentally friendly, and low-cost method to prepare N-doped adsorbents with outstanding CO2 adsorption property under 1 bar. Utilizing waste walnut shell as adsorbents precursor and NaNH2 as chemical activator and nitrogen source, porous adsorbents containing nitrogen are prepared at low temperature zone 400–500 °C. Also, by adjusting the activation temperature of the adsorbent and the ratio of NaNH2/AC, the pore structure and nitrogen content of the adsorbent are regulated to affect CO2 adsorption performance. The specific surface area of the prepared series of nitrogen-containing porous adsorbents is from70 m2/g to 419–1721 m2/g. The result indicates that the optimal adsorbent has the highest 5.22 mmol/g of CO2 adsorption capacity. A systematic study on the prepared series of adsorbents demonstrates that the narrow pore volume, pore structure and nitrogen content of the adsorbent jointly affected adsorption performance of CO2. Besides, these walnut shell-derived N-doped adsorbents show appropriate CO2/N2 selectivity and Qst. The numerous advantages of the cheap waste walnut shell adsorbents enjoy simple and low-temperature synthesis process indicating that they are outstanding substitution to CO2 adsorbents. The study hopes to further understand the synthesis of N-doped carbon and its carbon dioxide adsorption mechanism.

In the present work, an attempt has been made for the development of green and high efficiency acid pickling inhibitor based on the eco-friendly polyaspartic acid (PASP). In this view, cysteamine modified PASP (PASP-S) containing S atom was prepared by ring-opening reaction of polysuccinimide with cysteamine. The corrosion inhibition performance of PASP and PASP-S for mild steel in 0.5 M H2SO4 medium were evaluated using weight loss, electrochemical impedance and potentiodynamic polarization methods. The inhibition performance of PASP-S is greatly improved with a high efficiency of 93.9% (weight loss method) at a very low concentration of 100 mg L−1 at 298 K in comparison with unmodified PASP. The obtained results also indicate that PASP-S is a mixed inhibitor and the adsorption of PASP-S on the mild steel surface follows Langmuir adsorption isotherm. Theoretical chemical parameters are calculated using the Density Functional Theory method (DFT). The excellent inhibition performance of PASP-S is due to the presence of pendent functional sulfhydryl group, which can be confirmed by X-ray photoelectron spectroscopy (XPS) analysis of the mild steel samples. The present work provides a simple and effective pathway for synthesizing high efficiency acid pickling inhibitor by introducing a functional group into the PASP chains. Such chemical modification method may also be an effective strategy to improve the efficiency of other polymer acid pickling inhibitors.

A novel mesocellular silica foam (MCF) support were synthesized, which has different pore volumes and two different sizes of windows on the spherical cells. Tetraethylenepentamine (TEPA)-functionalized MCF adsorbents were then prepared for CO2 capture. The effects of support structure, capture temperature, SO2, and NO2 on the CO2 capture were investigated. The results show that the hierarchical window structure can improve the dispersion of amine species in the silica foams. In situ diffuse reflectance infrared Fourier transform spectroscopy results indicate that more adsorption sites can be exposed in the pores at high temperature for CO2 capture. The MCF-TEPA60% has the optimal capture amount of 4.75 mmol/g with 15 vol % CO2 at 75 °C. The SO2 and NO2 have a negative influence on the adsorption and regeneration properties of adsorbent due to the production of byproducts. However, the MCF-0.8-TEPA60% can maintain outstanding carbon dioxide adsorption capacity during 10 regeneration cycles.

Ordered mesoporous silica-carbon (MSC) were used as supports of Ni based catalysts for dry reforming of methane (DRM) reaction. The effects of preparation method and precipitant on the catalysts are investigated. The physical and chemical properties are discussed based on the H2-TPR, FTIR, XRD, TEM, H2-TPD and N2 adsorption/desorption characterization. It is found that the preparation method and choice of precipitants affect the catalysts significantly in terms of the properties and catalytic performance in DRM reaction. In detail, the catalysts prepared by the precipitation method show more highly dispersed Ni particles and further better catalytic activity than the impregnated catalyst. That is attributed to the forming Ni3Si2O5(OH)4 nanoflakes in the catalyst precursors with the existence of alkaline precipitants. And this Ni3Si2O5(OH)4 species bind the support more tightly than NiO in the impregnated Ni/MSC catalyst. Moreover, the choice of precipitants also influences the form of Ni3Si2O5(OH)4 species in the catalysts. Specially, the strong electrolytic capacity of NaOH gives the most Ni3Si2O5(OH)4 nanoflakes formed in Ni-MSC-1 catalyst, which results in the most highly Ni dispersity and further highest catalytic activity. Besides, the strong interaction between the Ni3Si2O5(OH)4 species and support are also advantageous to the resist sintering and formation of carbon deposition, that is related to the good catalytic stability of catalysts.

In order to relieve the amine agglomeration phenomenon in solid amine adsorbent and realize the efficient CO2 capture, a novel double-functionalized adsorbent was synthesized by grafting 3-aminopropyltriethoxysilane and impregnating tetraethylenepentamine, using original mesoporous silica molecular sieves as support. The effects of organic amine loading, gas flow rate and adsorption temperature on CO2 adsorption properties of adsorbent were studied. The results show that SBA-15(p)-AP-70T modified with 70% TEPA has the maximum N content (15.81 mmol/g) and the maximum saturated adsorption capacity (5.69 mmol/g) at 75 °C。Moreover, the CO2 adsorption capacity of this adsorbent can still remain about 5.2 mmol/g after 15 adsorption/desorption cycles. It is mainly because that the grafted APTES and residual P123 in the support pore provide space and hydrogen bonding functional groups for TEPA dispersion and fixation, while reduce the loss of TEPA during the cycle process. Therefore, compared with adsorbent modified by only TEPA, the adsorption capacity and stability of this adsorbent can be effectively improved. In addition, kinetic studies indicate that CO2 adsorption on SBA-15(p)-AP-70T is mainly chemisorption. According to the in situ DRIFTS results, CO2 adsorption mechanism on SBA-15(p)-AP-70T adsorbent is consistent with the zwitterion mechanism.

The inhibitory effect of radish leaf extract (RLE) on mild steel corrosion in 0.5 M H2SO4 was studied by the weight loss method and the electrochemical method. The results demonstrated that the efficiency of inhibition increased with an increase in the concentration of RLE and decreased with an increase in temperature. The inhibition performance reached 93% with 300 mg L−1 at 298 K. RLE behaved as a mixed-type inhibitor based on the cathode. The inhibition mechanism involved the adsorption of the active ingredients of RLE on the mild steel surface to prevent corrosion. The adsorption followed the Langmuir adsorption isotherm, and physical and chemical adsorption coexisted. The results were supported by SEM, quantum chemical calculations, FTIR and UV-visible spectroscopy analyses.

Activated carbon (AC) was treated with melamine to prepare nitrogen-doped carbon materials (AC-N), which used as support to prepare Co supported catalysts for CH4–CO2 reforming (DRM) reaction and its catalytic performance was investigated. The modified (Co/AC-N) and unmodified (Co/AC) catalyst were characterized by BET, H2-TPR, XRD, TEM, XPS, CO2-TPD and FTIR. It was found that the modified catalyst not only showed excellent stability, but also had better catalytic activity than the unmodified catalyst. Although the physical structure of modified catalysts is almost same with the unmodified catalysts, nitrogen and some oxygen functional groups such as pyridine nitrogen, pyrrole nitrogen, hydroxyl and oxygen incarbonyl groups were generated on the AC surface during the amination treatment. The generated surface nitrogen and oxygen functional groups affect not only influence the dispersion of active metals but affect the valence distributions of cobalt. Compared with the untreated catalyst, small active particle size with a narrow size distribution formed on the surface of N-doped catalyst. Moreover, the modified catalyst also provides more basic sites for the reforming reaction to accelerate the adsorption and dissociation of CO2 on the active site of the catalyst.

Recently, the heterogeneous advanced reduction processes (ARPs) for bromate (BrO3-) degradation have attracted considerable attention due to its stable performance and easy combination with UV disinfection. In this study, a UV/TiO2-Bi advanced reduction process (ARP) was established for BrO3- removal without adding external sacrificial agents. In the UV/TiO2-Bi ARP, Bi nanoparticles (NPs) doped on the TiO2 acted as hole trapping centers, while TiO2 NPs were used as reduction centers for the reduction of BrO3-, which enhanced the charge carrier separation. The UV/TiO2-Bi-1% ARP exhibited the highest BrO3- removal rate without the addition of sacrificial agents in the reaction solution compared to UV/TiO2 ARP and the UV/TiO2-Bi ARP at other Bi/Ti ratios. The result of 72% removal of 200 µg/L BrO3- at 60 min by 0.2 g/L TiO2-Bi-1% in tap water at pH 6.8 and 7.71 mg/L dissolved oxygen (DO) demonstrates the promising potential of the UV/TiO2-Bi ARP for the removal of BrO3- in practical applications. Compared to the 99.5% removal in deionized (DI) water at 60 min, lower BrO3- reduction in tap water was likely attributed to the consumption of photo-generated electrons by NO3– and the adsorption of natural organic matter on the surface of TiO2-Bi-1% nanocomposites. The study provides not only a novel BrO3- removal system with good photo-reduction performance, but also some guidance for the influence of constituents in raw water on the treatment of BrO3-.

Graphene-based electric power generation that converts mechanical energy of flow of ionic droplets over the device surface into electricity has emerged as a promising candidate for blue-energy network. Yet the lack of a microscopic understanding of the underlying mechanism has prevented ability to optimize and control the performance of such devices. This requires information on interfacial structure and charging behavior at the molecular level. Here, we use sum-frequency vibrational spectroscopy to study the roles of solvated ions, graphene, surface moiety on substrate and water molecules at the aqueous solution/graphene/polymer interface. We discover that the surface dipole layer of the neutral polymer is responsible for ion attraction toward and adsorption at the graphene surface that leads to electricity generation in graphene. Graphene itself does not attract ions and only acts as a conducting sheet for the induced carrier transport. Replacing the polymer by an organic ferroelectric substrate could allow switching of the electricity generation with long durability. Our microscopic understanding of the electricity generation process paves the way for the rational design of scalable and more efficient droplet-motion-based energy transducer devices.

In order to investigate the influence of support structure properties on CO2 capture performances of solid amine adsorbents, a novel three-dimensional disordered porous silica (3dd) with hierarchical pore networks was developed and then compared to other three materials as adsorbent support, namely, hierarchical porous silica (HPS), MCM-41, and SBA-15. They were all functionalized with tetraethylenepentaamine (TEPA) to prepare CO2 adsorbents. The adsorbents’ ability to capture CO2 was examined on a fixed-bed reactor. When these supports had 60 wt% TEPA loading, the amounts of CO2 captured followed the order 3dd > HPS > SBA-15 > MCM-41 at 75 °C; the adsorption capacities were 5.09, 4.9, 4.58, and 2.49 mmol/g, respectively. The results indicate that a larger pore volume can promote the dispersion of amine species to expose more active sites for CO2 capture. The larger pore size can decrease the CO2 diffusion resistance. High surface area is not an important factor in determining capture performance. In addi...

In this study, we have developed a kind of single-layer graphene-based surface plasmon resonance (SLG-SPR) biosensor with wavelength interrogation to detect C-reactive protein (CRP) by sandwich immunoassay. For the nature of the biosensor itself, with the decrease of the incidence angle (θ), resonance wavelength (λR) increased gradually. The refractive index sensitivity (S) and θ are inversely proportional relationship while S and λR are positively proportional relationship. Then we studied two kinds of sensitivity properties of these two SPR biosensors respectively. The refractive index (RI) sensitivity of the two biosensors is approximately the same and the high sensitivity of SLG-SPR biosensor due to the excellent adsorption properties of graphene. The experiment shows that the changes in resonance wavelength (uλR) of SLG-SPR biosensor are higher than that of the gold film based SPR (Au-SPR) biosensor when the final sandwich structures were formed. Meanwhile, we have applied the Fresnel reflection equations and Bruggeman approximation formula to calculate the volume fractions of adsorbates in different adlayers, and the dispersion curves of the effective RI of adsorbates with different volume fractions of adlayers and the cAb isothermal adsorption curves that conforms to Langmuir equation were obtained. In conclusion, the SLG-SPR biosensor with a higher detection sensitivity than the conventional Au-SPR biosensor in detecting CRP and it has the advantages of low-cost, stability, highly efficient for the clinical determination of CRP levels.

SBA-15(P) mesoporous material with 2D hexagonal was synthesized as the precursor, then a series of Amine-functionalization SBA-15(p)-xTEPA CO2 adsorbents were prepared by impregnating with TEPA. The adsorbents were characterized using BET, XRD, FTIR, TEM, TGA and In situ IR DRIFTs. Characterization results show that additional impregnated TEPA has a negative effect on the textural properties of adsorbents and additional impregnated TEPA has not change the channel structure of the adsorbent. It also is found that the synergistic effect of TEPA and P123 enhance the initial decomposition temperature and enhance the stability of adsorbent. Compared with SBA-15-60TEPA, SBA-15(p)-60TEPA (SP60T) has better reusability and cyclic performance. After 9 times cycle, the SP60T sorbent still adsorbs around 5.0 mmol/g of CO2 from 20% CO2 in N2 at 75 °C and 1 atm, CO2 adsorption capacity only reduces 7.8%. It is mainly because that the template in carrier makes TEPA evenly dispersed, effectively prevent the TEPA reunion and loss, and improve the utilization ratio of amine. According to adsorption dynamics and inactivation model, CO2 adsorption of SP60T is mainly chemical adsorption. The in situ infrared spectroscopy reveals that CO2 adsorption of SP60T follows anionic and cationic mechanisms.

Water adsorption on phosphorene has fundamental importance to device development from black phosphorus, but the stable adsorption configuration remains in confusion. Here we explore the water adsorption configurations on phosphorene through comprehensive first principle calculations. It is found that water takes an optimal adsorption configuration on phosphorene with one of the hydrogen atoms pointing to the surface of phosphorene. This optimal adsorption configuration is significantly more stable than all the configurations reported previously for the strongest van de Walls interaction between the adsorbed water and the phosphorene compared to other adsorption configurations. It is also shown that water serves as an acceptor in the optimal adsorption configuration, clarifying the confusing results from less stable configurations.

To improve the corrosion inhibition efficiency of eco-friendly polyaspartic acid (PASP) for mild steel in acidic solutions, PASP/N-(3-aminopropyl)imidazole (PD-1) and PASP/N-(3-aminopropyl)-imidazole-co-n-dodecylamine (PD-2) were chemically synthesized by the facile ring-opening reaction of polysuccinimide. Inhibition efficiencies of PD-1 and PD-2 for mild steel in a 0.5 M H2SO4 solution were investigated by electrochemical measurements (electrochemical impedance and polarization) and the weight loss method. In comparison with PASP, PD-1 and PD-2 show improved inhibition efficiencies due to the functional groups. In particular, PD-2 shows superior corrosion inhibition capacity, and the efficiency is up to 94% at a relatively low concentration of 100 mg L−1 at 298 K, as determined by potentiodynamic polarization measurements. Surface analysis of mild steel with PD-2 as an inhibitor clearly indicates that the inhibitor molecules adsorb on the steel surface and efficiently inhibit the corrosion of mild steel. The present work provides very meaningful results in designing and preparing new polymer inhibitors with high inhibition efficiency.

For a CdS-based photocatalyst, both the photocorrosion resistance and the rapid H2-production reaction are highly required for improving its photocatalytic H2-production performance. In this study, a facile strategy was reported to simultaneously realize an improved photocorrosion resistance and rapid interfacial H2-evolution reaction of CdxZn1−xS solid–solution photocatalysts in a sulfur-rich S2−/SO32− solution. Here, the suspensible CdxZn1−xS nanocrystal photocatalysts are prepared by a one-step co-precipitation route through the direct introduction of Zn2+/Cd2+ mixing ions in a sulfur-rich Na2S–Na2SO3 solution, and the resultant CdxZn1−xS nanocrystals (ca. 5 nm) display a suspensible structure owing to the numerous and selective adsorption of S2−/SO32− on the surface of these CdxZn1−xS nanocrystals. It is found that the bandgap structure of CdxZn1−xS (from 2.25 to 3.52 eV) nanocrystals can be easily controlled by adjusting the Cd2+/Zn2+ molar ratio. The photocatalytic experimental results suggested that the suspensible CdxZn1−xS nanocrystal photocatalysts clearly displayed an excellent photocatalytic H2-production performance, and the suspensible Cd0.6Zn0.4S nanocrystals exhibit the highest photocatalytic H2-generation performance of 717.19 μmol h−1, a value higher than that of the sole CdS (320.99 μmol h−1) and ZnS (5.89 μmol h−1) by a factor of 2.2 and 121.8 times, respectively. Based on the experimental results, a possible S2− active site-mediated mechanism accounted for the high H2-production activity of the suspensible CdxZn1−xS nanocrystals, namely the numerous adsorbed S2− ions not only function as efficient hole scavengers to rapidly consume the photogenerated holes, resulting in an improved photocorrosion resistance of suspensible CdxZn1−xS nanocrystals, but also serve as effective H+-capturing active sites to accelerate the interfacial H2-production reaction. Meanwhile, an optimum bandgap structure of suspensible CdxZn1−xS nanocrystals is also extremely required for promoting the photocatalytic H2-production activity. This research may provide advanced insights for developing stable and high-activity photocatalytic materials.

Pichia kudriavzevii YB5, mutated from Pichia kudriavzevii A16 with a strong ability to remove cadmium ions, was immobilized by polyurethane foam and alginate gels in this work. The immobilization conditions were optimized as follows: sodium alginate concentration of 2% (w/v), calcium chloride concentration of 2% (w/v), biomass dose of 1 × 109 cell/mL, and cross-linking time for 4 h. Then, the results of batch adsorption experiments showed that the removal capacity of prepared bioadsorbent was significantly affected by the pH of media, contact time, and the initial Cd(II) concentration, and a suitable adsorption conditions of Cd(II) could be achieved with a pH value of 6.0 at 20 °C for 90 min. Kinetic and isothermal results indicated the behavior of Cd(II) adsorption onto immobilized P. kudriavzevii YB5 fitted to the pseudo-second-order kinetic equation and the Langmuir adsorption model. Thermodynamic results showed that the Cd(II) adsorption process was endothermic and spontaneous in nature. Besides, the Cd(II) removing capacity of the prepared bioadsorbent was also tested in the oyster hydrolysates, showing an average removal rate of 54.35%. Thus, the immobilized P. kudriavzevii YB5 adsorbent had great potential for application in aquatic products to ensure the food safety.

The application of photocatalytic oxidation (PCO) in VOCs abatement is greatly limited by catalytic deactivation and inefficiency. In this study, mesoporous TiO2 was prepared by a one-step hydrolysis method via varying the calcination temperature and used for photocatalytic oxidation of gaseous benzene. Results revealed that the calcination temperature significantly affects the structural properties and catalytic activity of TiO2. The fabricated mesoporous TiO2 exhibited much better catalytic activity and stability towards benzene degradation compared to commercially-available TiO2 (P25) which suffered from quick deactivation and low efficiency. The samples calcined at 400 °C showed a good mesoporous structure and superior capacity for benzene adsorption, which led to the best photocatalytic activity. VUV irradiation in the PCO process greatly enhanced benzene degradation and exhibited a benzene removal efficiency of 80% while it was less than 10% under UV irradiation. VUV photolysis and O3 generated from VUV irradiation made a major contribution to benzene degradation in the VUV-PCO process.

In this paper, a framework for conceiving an index that can quickly evaluate biogas conversion potential (BCP) of sewage sludge (SS) was proposed based on the surface site of sludge particulate (SP). As enzymes, the cornerstones of metabolism, are responsible for the efficiency of anaerobic digestion (AD) process, the adsorption of hydrolytic enzyme on the sludge with different surface site density (SSD) of SP was studied. The experimental results suggest that the surface site of SP can be considered as the binding site for hydrolytic enzyme, as confirmed by organic solubilisation tests of the sludge. To further explore the relationships between SSD and BCP of SS, the biochemical composition and long-term biochemical methane potential (BMP) tests of different sludge samples were conducted. The results show that both the methane production rate constant (k) and net cumulative methane production (NCMP) increased as the SSD values increased. Analyses of the statistical and fitting mathematical models for the SSD, biochemical composition, k, and NCMP revealed a significant positive linear correlation between k and NCMP versus SSD can be found (R 2 = 0.910, P 2 = 0.939, P

The purpose of this study was to establish an efficient modern strategy for the reduction and control of cadmium (Cd) content in the crab viscera homogenate. To this end, the coupling of an artificial neural network (ANN) technique with the genetic algorithm (GA) method and compared the performance of GA-ANN with response surface methodology (RSM) were demonstrated in the prediction and optimization of the ultrasonic-assisted adsorption of Cd using a aerogel adsorbent. On the basis of single factor test, the data sample was established by Box–Behnken Design, and the effects of ultrasonic time, temperature, the addition amount of aerogel, and pH on the removal rate of Cd were researched. The results revealed that the RSM and GA-ANN models had relative errors and coefficients of determination R2 values of 3.90%, 0.8440, and 1.79%, 0.9283, respectively, suggesting that GA-ANN is more accurate than RSM. The maximum percentage of Cd extracted (79.13%) was obtained using GA-ANN model as ultrasonic time of 87 min, temperature of 81 °C, adsorbent dosage of 0.07 g, pH of 3.20. In conclusion, the present results provide an effective method for optimizing multi-technology coupling to reduce the toxic heavy metal content in aquatic products.

Electrocatalytic nitrogen fixation provides an alternative approach to replace the Haber-Bosch process for ammonia synthesis. We systematically investigated transition metal atoms (Fe, Co, Mo, Ru) anchored on defected V2C for electrocatalytic nitrogen fixation based on first-principles calculation. The calculated results show that the overpotential of NRR on Mo doped V2C is only 0.49 eV along the mixed enzyme pathway, which is much lower than that of pristine V2C (0.61 eV). Such low overpotential is related to the cooperation of the diatom of Mo and V, which promotes the activation of nitrogen molecules. Besides, the adsorption of nitrogen on Mo doped V2C is significantly greater than that of H+ . Therefore, HER can be effectively inhibited. The extremely low overpotential and good selectivity make Mo/V 2C a potential catalyst for NRR.

A trimodal porous support with special trimodal pore structure has been prepared by physically mixing the silica gel (HPS) and SBA-15 and then devoted to fabricate TEPA-functionalized adsorbent for CO2 capture. The trimodal multistage mesopores structure can promote the TEPA dispersion and mitigate the mass-transfer resistance in the adsorbent and, hence, improve capture performance, compared to the single mesoporous support. The influence of the mass ratios of HPS to SBA-15, amine loaded amount, CO2 concentration, adsorption temperatures, and water vapor were studied. The CO2-saturated adsorption amount of 5.05 mmol/g was obtained at 75 °C in dry N2 flow containing 15 vol % CO2 when the mass ratio of SBA-15 to HPS was 1:2 with 50 wt % TEPA loadings. Moreover, the CO2-saturated adsorption amount presented a 16% improvement in humid N2 flow containing 15 vol % CO2 flow at 75 °C. In addition, the S2HPS-TEPA50% also demonstrated good stability after 10 adsorption/desorption cycles. Based on in situ DRIFTS re...

A kind of hierarchical porous silica (HPS) was synthesized in a relatively mild condition and then devoted as the supports to fabricate TEPA-impregnated adsorbents for CO2 adsorption. HPS has different pore size distribution and the huge pore volume. These structure characteristics of HPS can mitigate the mass transfer resistance which occurs more serious in traditional carrier materials with single smaller channel. The CO2 adsorption performances of modified HPS were investigated in a homemade fixed bed reactor under different conditions. The HPS exhibited maximum CO2 adsorption capacities of 5.01 mmol/g when 60 wt.% TEPA loaded. It presented better TEPA loading properties and higher CO2 adsorption capacities than the majority of the single ordered mesoporous adsorbents according to the literature. When the adsorption experiments were repeated ten times, the amount of CO2 capture reduces from 5.01 mmol/g to 4.7 mmol/g, only 6.1% reduction. And the deactivation model which can describe the absorption of CO2 was adopted under different experiment conditions. In all these cases, the experimental data of CO2 adsorption gave a good agreement with the predicted results by the breakthrough model.

In this article, a comparison will be made concerning the advantages and disadvantages of five kinds of coal mine methane (CMM) deoxygenation method, including pressure swing adsorption, combustion, membrane separation, non-metallic reduction, and cryogenic distillation. Pressure swing adsorption has a wide range of application and strong production capacity. To achieve this goal, adsorbent must have high selectivity, adsorption capacity, and adequate adsorption/desorption kinetics, remain stable after several adsorption/desorption cycles, and possess good thermal and mechanical stabilities. Catalytic combustion deoxygenation is a high-temperature exothermic redox chemical reaction, which releases large amounts of thermal energy. So, the stable and accurate control of the temperature is not easy. Meanwhile partial methane is lost. The key of catalytic combustion deoxygenation lies in the development of high-efficiency catalyst. Membrane separation has advantages of high separation efficiency and low energy consumption. However, there are many obstacles, including higher costs. Membrane materials have the requirements of both high permeability and high selectivity. The development of new membrane materials is a key for membrane separation. Cryogenic distillation has many excellence advantages, such as high purity production and high recovery. However, the energy consumption increases with decreasing CH4 concentrations in feed gas. Moreover, there are many types of operational security problems. And that several kinds of deoxygenation techniques mentioned above have an economic value just for oxygen-bearing CMM with methane content above 30%. Moreover, all the above methods are not applicable to deoxygenation of low concentration CMM. Non-metallic reduction method cannot only realize cyclic utilization of deoxidizer but also have no impurity gases generation. It also has a relatively low cost and low loss rate of methane, and the oxygen is removed thoroughly. In particular, the non-metallic reduction method has good development prospects for low concentration oxygen-bearing CMM. This article also points out the direction of future development of coal mine methane deoxygenation.

Ca-promoted Co-based/AC catalysts prepared with various Ca/Co ratios by using impregnation method were applied to synthesis gas production via CO2-CH4 reforming reaction. The influences of preparation methods on the physico-chemical characteristics, catalytic activities and stability of the catalysts were examined in a fixed-bed reactor. The basic physico-chemical characters of prepared catalysts were studied by the H2-TPR, XRD and XPS and BET methods. H2-TPR, XRD and XPS results confirmed that cobalt dispersion improving, the interaction between cobalt and calcium intensify and the sintering of cobalt mitigation is due to calcium addition. Results of XRD and H2-TPR also show that there was a new crystal substance Ca3Co2O6 formed, which has most strong influence on the catalytic activity enhancing and the anti-coking ability of CO2-CH4 reforming catalyst. Through the SEM analysis of the used catalyst after CO2-CH4 reforming, the Co-Ca/AC catalysts were also confirmed to show better sinter-stability. In addition, the addition of calcium can improve the carbon dioxide adsorption properties, so that it is easy to eliminate carbon deposited on the surface of the catalyst by gasification. In particular, the catalyst with 14 wt.% of calcium addition revealed a good activity and anti-sintering ability in CO2-CH4 reforming. On the basis of experimental observations and literature reviewed, a simple carbon dioxide reforming of methane into syngas mechanism over a cobalt/AC catalyst promoted by Ca is proposed.

Uniform α-Fe nanoparticle anchored hierarchical carbon nanofibres were prepared by PAN/FeCl3 co-electrospinning and self-reduced pyrolysis. Profiting from active zero-valent iron and high adsorption capacity, the composite nanofibres exhibited excellent activity, high stability and easy magnetic separation in the PMS activation for organic pollutant oxidative degradation.

Different activated carbons and manganese-modified activated carbons were prepared as deoxidizers for the low-concentration coalbed methane deoxidation. The results show that the deoxidation performance of the different activated carbons is affected by raw materials for preparation of deoxidizers. One type of activated carbon exhibited the best performance of oxygen removal, due to the relatively low ash content and better adsorption performance. Experimental results show that the manganese-modified deoxidizers exhibit an excellent deoxidation efficiency at low temperature. At 200 oC, one kind of manganese-modified activated carbons decreased the oxygen content to less than 1 vol%, which could maintain about 600 min. This indicated that the addition of manganese greatly improved the reactivity of oxygen with activated carbon. Characterization results demonstrated that the physical structure and species types of oxygen of activated carbons, and manganese have important effects on the activity of deoxidizers in different temperature ranges.

Based on efficiency and environmental concerns, the development of porous carbon from waste and biomass materials has attracted extensive attention as a novel approach. In this study, poplar sawdust was an inexpensive carbon precursor, sulfur-containing waste liquid (SCWL) was used as a modifier to turn waste into treasure, and potassium oxalate (K2C2O4) was a mild activator, successfully prepared N, S, O co-doped new porous activated carbon with excellent CO2 capture performance. The heteroatom doping and pore structure can be controlled by using SCWL and K2C2O4, and adjusting the activation temperature. The best sample (PCSK-2-3-800) prepared with SCWL and K2C2O4 showed excellent CO2 adsorption performance, reaching 3.82 and 5.61 mmol/g under normal pressure at 25 and 0 °C, respectively. This is attributed to the synergy of porous structure and surface chemistry. The pore structure parameter results showed that K2C2O4 promotes the development of activated carbon pore structure. The specific surface area, micropore volume and narrow micropore volume of PCSK-2-3-800 are 1418 m2/g, 0.55 cm3/g and 0.43 mL/g, respectively. The characterization results of FTIR and XPS showed that the addition of SCWL can successfully introduce heteroatoms into the carbon skeleton, and form CO2-philic active sites on the surface of the porous carbon. Both aspects promoted the adsorption of CO2. In addition, the PCSK-2-3-800 sample has a moderate adsorption heat of 27.13 kJ/mmol, good adsorption selectivity of CO2 and N2 is 13, and excellent recyclability, which is very promising for CO2 separation or storage. This paper develops a sustainable scheme for the first-time using biomass and SCWL to develop a new solid carbon adsorbent, which provides useful information and inspiration for capturing CO2.

To enhance the adsorption performance of 2D graphene-like materials Ti3C2Tx (T = OH, O, F) on methylene blue (MB) and realize its reuse, sodium alginate (SA) was used to immobilize Ti3C2Tx to form Ti3C2Tx/SA beads. The beads were fabricated with Ti3C2Tx powder and SA by ionic crosslinking. Based on the SEM, FTIR and XRD analysis, Ti3C2Tx was bound to SA tightly, which avoided the loss of adsorbent and improved the adsorption effect. The adsorption characteristics of MB were investigated at different material ratios, temperature, pH and initial concentration. The results indicated that Ti3C2Tx/SA-30% was chosen as the appropriate mass ratio, the maximum adsorption capacity of which was 92.17 mg/g at pH 7 and 298 K. The MB adsorption efficiency was maintained 81.36% after three cycles. The adsorption process was conformed to pseudo-second-order kinetics, and fitted well with Langmuir isotherm model. Thermodynamic analysis suggested that the process of MB adsorbed on Ti3C2Tx/SA beads was endothermic and spontaneous. The results showed that Ti3C2Tx/SA beads had potential application in pollutants removal for efficient adsorption and superior reusability.

Dehydration of lignite primarily occurs in two stages, namely, removal of surface moisture and decrease in oxygen-containing functional groups and moisture stage. Moisture on the lignite surface could be removed at temperatures below 100 °C. However, parts of oxygen-containing functional groups were removed first followed by the removal of the adsorbed moisture at temperatures in the range 100–300 °C. Dehydration time increased with an increase in the dehydration load and heat transfer distance. At surface moisture of 7 wt.%, temperature of lignite increased rapidly. Higher temperature of combustion chamber yielded shorter removal times for surface moisture and oxygen-containing functional groups. Based on the rate of increase of lignite temperature and associated heat transfer process, coking chamber could be divided into three zones: the near, middle, and remote zones. The near zone temperature curve was determined to be a convex function ∂ 2 T ∂ τ 2 ≤ 0 ; however, the middle zone temperature curve was determined to be a concave function ∂ 2 T ∂ τ 2 ≥ 0 ⋅ ∂ 2 T ∂ τ 2 = 0 and ∂ T ∂ τ = k were the boundary indices of the middle and remote zones. 100 °C isothermal surface movement rate was found to be affected by the heat transfer capacity and dehydration load. Center temperature distribution of coking chamber was made uniform by steam, and temperature of HM7% was the most uniform distribution.

The effects of final pyrolysis temperature Tend from 300 ºC to 550 ºC, heating rates β of 2 ºC/min, 3 ºC/min and 5 ºC/min, retention time RT from 45 min to 90 min, and the moisture content MC from 0 to 70% on characteristics of the pyrolysis char from sewage sludge were investigated using a tube furnace in this study. The resulting chars were characterized by sorption of nitrogen (surface area and pore volume). Their adsorption characteristics were evaluated via iodine value and methylene blue value. Either the pore structures or adsorption characteristics depend on the pyrolysis processing and moisture content of the sludge precursors. In terms of iodine value and surface area of the char, Tend of 450 ºC, RT of 75 min and β of 3 ºC/min proved the optimum combination of pyrolysis parameters. The chars have an undeveloped mesopore and macropore structure and a developed micropore structure. The sodium phenoxide adsorption equilibrium data fit well with the Langmuir model of adsorption, suggesting monolayer coverage of sodium phenoxide molecules at the surface of the char. Its adsorption mechanism is mainly physical in nature, enhanced by chemisorption.

Oil-field wastewater from polymer flooding (OWPF) is difficult to deal with because it contains a high concentration of partially hydrolyzed polyacrylamide (HPAM), which stabilizes the wastewater. Coagulation–flocculation with polyepicholorohydrin–dimethylamine (EPI-DMA) and polymeric aluminum ferric chloride (PAFC) was used to optimize the treatment of OWPF. HPAM and COD removal were optimized using the response surface method (RSM), based on the Box–Behnken design (BBD). The variables EPI-DMA dose, PAFC dose, and pH were selected as the factors in the RSM to investigate their individual and interaction effects on the response values, HPAM and COD removal efficiencies. The results showed that HPAM and COD removal efficiencies of 95.4 and 85.7%, respectively, could be reached using 0.65 mg/L EPI-DMA, 924 mg/L PAFC, and pH 5.51. Fourier transform infrared spectroscopy, zeta potential, particle size analysis, scanning electron microscopy, and energy dispersive spectroscopy were used to study the mec...

Reusing wastewater can enormously reduce environmental pollution and save water. One of the key obstacles to reuse is the scaling caused by calcium (Ca) ions and humic matter (HM). The interactions among HM, Ca ions and cation-exchange resins (CERs) during the water softening process were explored via lab-scale and pilot-scale tests. Surface topography, pore structure, and surface molecular structure of the CERs were determined using an atomic-force microscope, an automatic mercury porosimeter, a laser-Raman spectrum and X-ray photoelectron spectroscopy, respectively. The surface charge of CERs was assessed by measuring zeta potential. Experimental results showed that HM can react with Ca-ions to form HM–Ca+ and Ca ions can act as a bridge for HM and CER, suggesting that Ca ions and HM can be simultaneously removed by CERs. Kinetic analyses indicate that a pseudo-first order equation was able to accurately describe the overall adsorption kinetics and diffusion of Ca ions through a liquid film of CER was the rate-determining step for the overall adsorption process. Further investigation revealed that during the first 60 minutes of adsorption, the effect of HM on the CER adsorption kinetics can be described well by pseudo-first and pseudo-second order equations. This indicates that diffusions of Ca ions, HM, and HM–Ca+ and their interactions were equivalent for controlling the initial stage of adsorption. In addition, 99% of Ca ions and 30–60% of HM in wastewater were removed in the pilot-scale test, suggesting that CERs have significant potential to remove Ca ions and HM simultaneously in wastewater.

A novel type of porous magnetic microsphere (Fe3O4@HCP) was firstly synthesized just via one-step Friedel–Crafts alkylation promoted by FeCl3. This universal and facile method to fabricate porous magnetic microspheres possesses distinct advantages such as cheap reactants, mild reaction conditions, a short reaction time and a simple post-treatment process. The core–shell spheres with a well-defined and uniform morphology possess a high Brunauer–Emmett–Teller specific surface area (770 m2 g−1). Besides, the magnetization saturation value reaches up to 18 A m2 kg−1 which is high enough to separate Fe3O4@HCP from aqueous solution. Fe3O4@HCP possesses fast adsorption kinetics and an excellent adsorption capacity for organic dyes: methyl orange (211 mg g−1) and fuchsin basic (231 mg g−1). The adsorption-saturated Fe3O4@HCP composites can be easily collected by an external magnetic field and reused at least 3 times after simple Soxhlet extraction and drying.

A series of N-doped CO2 adsorbents were prepared by using waste walnut shell as the raw material, urea as nitrogen source, H3PO4 as a pretreatment agent and KOH, K2CO3 and ZnCl2 as the activators. Result indicates that both the pore structure and nitrogen content of the adsorbent together affect the CO2 adsorption capacity. HAC-850-KOH showed excellent CO2 adsorption capacity (5.13 mmol/g) at 0 °C and atmospheric pressure probably because of its large specific surface area (SBET 2354 m2/g). HAC-750-ZnCl2 has the higher CO2 adsorption capacity (0.6 mmol/g) at 25 °C and 0.15 bar due to its highest nitrogen content (9.32 wt%). HAC-850-K2CO3 has a good selectivity of 21.5 and cycle performance may be somewhat associated with its pore structure and nitrogen content, and the initial heat of adsorption is 44 kJ/mol. The result indicates that the pore structure of the adsorbent has a great influence on the adsorption performance under high pressure; the nitrogen content of the adsorbent has a decisive influence on the adsorption performance of the adsorbent under low pressure. At the same time, the pore structure properties of the prepared adsorbent have a more significant effect on the adsorption performance at lower temperatures. This work provides an effective guide to synthesize biomass-based adsorbent for different application conditions, especially in the selection of activators.