Heteroatomic Modification of Solid-Waste-Based Mesoporous Carbon for Volatile Organic Compound Adsorption

Solid-waste-based activated carbon(AC)was utilized as a carbon source to synthesize a series of carbon-based functional material RAC-X(X=P and S,where P and S denote phosphoric and sulfuric acids,respectively).The toluene adsorption capacities of the regeneration AC(RAC)samples can be significantly improved by adopting the heteroatomic modification strategy.RAC-P and RAC-S have the same specific surface area(1156 m^(2)/g)and similar porous structures.However,they have different toluene adsorption capacities,with 316.22 mg/g for RAC-P and 460.12 mg/g for RAC-S,which are 1.6 and 2.4 times greater than that for RAC.The X-ray photoelectron spectroscopy measurements showed that the increase in the amount ofπ–π^(2)chemical bond over the AC surface results in the improvement of the toluene adsorption performance.The density functional theory results showed that the S-containing functional groups loaded near the defect sites of RAC-S promote toluene adsorption.Moreover,reusability tests showed that RAC-S still retains 86%of its adsorption activity after four consecutive adsorption–desorption experiments.This indicates that the heteroatomic modification method affords excellent toluene adsorption performance and recycling practicability,which not only is beneficial for achieving the rational utilization of solid waste resources but also provides a practical method for the efficient elimination of volatile organic compounds.

Enhancement of CO_2 adsorption on nanoporous chromium terephthalate(MIL-101) by amine modification

Carbon dioxide （CO2） adsorption on a standard metal-organic framework MIL-101 and a pentaethylenehexamine modified MIL-101 （PEHA- MIL-101） are investigated and compared in this study. The adsorbent samples were characterized by XRD, FT-IR and nitrogen adsorption- desorption isotherms analysis. CO2 adsorption capacity was measured by a volumetric method. MIL-101 and PEHA-MIL-101 exhibited CO2 adsorption capacities of 0.85 and 1.3 mmO1CO2/gadsorbent at 10 bar and 298 K, respectively. It is observed that CO2 adsorption capacity was fairly improved about 50% after amine modification.

Modification of Nylon Membrane Used for Affinity Adsorption

Nylon membrane was modified by binding with polyhydroxyl-containing materials to increase its hydrophilicity and reduce its nonspecific interaction with proteins. The effect of binding hydrophilic materials on amount of ligand bound-Cibacron Blue F3GA (CBF) was investigated. Experimental data showed that the amount of CBF bound can be increased significantly after binding of hydrophilic materials.

SURFACE MODIFICATION OF POLYPROPYLENE MICROPOROUS MEMBRANES BY THE ADSORPTION OF NON-IONIC SURFACTANTS

Surface modification by physical adsorption of a series of non-ionic surfactants including Tween 20, Tween 40, Tween 60, Tween 80 and Tween 85, was accomplished on polypropylene microporous hollow fiber and flat membranes. The adsorption curve of the membrane surface was analyzed by weight measurements and the typical results showed a twoplatform character similarly. Differences in the degree and curve shape of adsorption resulting from such factors as concentration, temperature, as well as water cleaning time were observed for Tween 85 among other Tweens. Attenuated total reflection - Fourier transform infrared spectroscopy analysis and field emission scanning electron microscopy observation showed that the adsorption of Tween on polypropylene microporous membrane （PPMM） is effective and occurs mainly in the pores of PPMMs at low adsorption amount, and on the membrane surface also at high adsorption value.

Plasma Modification of Activated Carbon Fibers for Adsorption of SO_2

Viscose-based activated carbon fibers （VACFs） were treated by a dielectric-barrier discharge plasma under the feed gas of N2. The surface functional groups of VACFs were modified to improve the adsorption and catalysis capacity for SO2. The surface properties of the untreated and plasma-treated VACFs were diagnosed by SEM, BET, FTIR, and XPS, and the adsorption capacities of VACFs for SO2 were also compared and discussed. The results show that after the plasma treatment, the external surface of VACFs was etched and became rougher, while the surface area and the total pore volume decreased. FTIR and XPS revealed that nitrogen atoms were introduced onto the VACFs surface and the distribution of functional groups on the VACFs surface was changed remarkably. The adsorption characteristic of SO2 indicates that the plasmatreated VACFs have better adsorption capacity than the original VACFs due to the nitrogen functional groups and new functional groups formed in modification, which is beneficial to the adsorption of SO2.

Preparation and modification of activated carbon for benzene adsorption by steam activation in the presence of KOH

A series of activated carbons from Taixi anthracite were prepared by steam activation in the presence of KOH and then they were modified by different methods. The regulation of porosity and the modification of surface chemistry were carried out with the aim to improve the benzene adsorption capacity of activated carbon. The influences of KOH and activation process parameters including activation temperature, activation time and steam flow rate on porosity of activated carbon were evaluated, and the effect of modification methods on surface chemistry was investigated. Also, the relationship between benzene adsorption capacity and porosity and surface chemistry was analyzed. Results show that activation temperature is the dominant factor in the activation process; the introduction of KOH into the raw material can enhance the reactivity of char in activation process, meanwhile it shows a negative effect on the porosity development, especially on the mesopore development. Results of FTIR analysis indicate that anthracite-based activated carbon with condensed aromatics and chemically inert oxygen does not present the nature to be surface modified. Besides, benzene adsorption capacity has an approximate linear relationship with surface area and in our preparation, benzene adsorption capacity and surface area of activated carbon are up to 1210 m 2 /g and 423 mg/g, respectively.

Preparation and Modification of Micro-Mesoporous Carbon Materials for Toluene Adsorption

In the process of toluene adsorption, the choice of adsorbent is the key. In this work, micro-mesoporous carbon materials were prepared and characterized. The synthesis process was performed by using MCM-41 as the template, and sucrose and furfuryl alcohol as the carbon source, respectively. The toluene adsorption capacity of studied adsorbents was evaluated under different toluene initial concentration, temperature and bed height. In order to further improve the adsorption capacity, nitric acid was used for modification of the selected adsorbent. The adsorption performance after modification was also investigated. The prepared carbon materials were characteristic of typical type IV isotherms and pore size distribution was focused on micropores and mesopores. Compared with MCM-41, the prepared carbon materials showed high toluene adsorption capacity. After modification the specific surface area and oxygen groups of adsorbent were increased, making the adsorption capacity increase from 185.3 mg/g to a maximum value of 514.7 mg/g. The adsorption capacity of adsorbent mainly depended on its surface area and surface chemical property.

SURFACE MODIFICATION OF TITANIUM FILMS WITH SODIUM ION IMPLANTATION:SURFACE PROPERTIES AND PROTEIN ADSORPTION

Sodium implanted titanium films with different ion doses were characterized to correlate their ion implantation parameters. Native titanium films and ion implanted titanium films were characterized with combined techniques of X-ray photoelectron spectroscopy （XPS）, atomic force microscopy （AFM）, and light microscopy （LM）. The surface presented increased sodium concentration on treated titanium films with ion dose increasing, except for the group with the highest ion dose of 4×10^17ions/cm^2. XPS depth profiling displayed that sodium entered titanium film around 25-50nm depth depending on its implantation ion dose. AFM characterization showed that sodium ion implantation treatment changed the surface morphology from a relatively smooth titanium film to rough surfaces corresponding to different implantation doses. After sodium implantation, implanted titanium films presented big particles with island structure morphology. The surface morphology and particle growth displayed the corresponding trend. Fibrinogen adsorption on these titanium films was performed to correlate with the surface properties of treated titanium films. The results show that protein adsorption on ion-implanted samples with dose of 2×10^17 and 4×10^17 are statistically higher （p 〈0.01） than samples treated with dose of 5×10^16 and 1×10^17, as well as the control samples.

Surface Modification of (001) Facets Dominated TiO2 with Ozone for Adsorption and Photocatalytic Degradation of Gaseous Toluene

This study investigated the positive effect of surface modification with ozone on the photocatalytic performance of anatase TiO2 with dominated (001) facets for toluene degradation. The performance of photocatalyst was tested on a home-made volatile organic compounds degradation system. The ozone modification, toluene adsorption and degradation mecha-nism were established by a combination of various characterization methods, in situ diuse reectance infrared fourier transform spectroscopy, and density functional theory calculation. The surface modtication with ozone can signiticantly enhance the photocatalytic degradation performance for toluene. The abundant unsaturated coordinated 5c-Ti sites on (001) facets act as the adsorption sites for ozone. The formed Ti-O bonds reacted with H2O to generate a large amount of isolated Ti5c-OH which act as the adsorption sites for toluene, and thus signi- cantly increase the adsorption capacity for toluene. The outstanding photo- catalytic performance of ozone-modified TiO2 is due to its high adsorption ability for toluene and the abundant surface hydroxyl groups, which produce very reactive OH· radicals under irradiation. Furthermore, the O2 generated via ozone dissociation could combine with the photogenerated electrons to form superoxide radicals which are also conductive to the toluene degradation.

Surface Modification of Commercial Activated Carbon (CAG) for the Adsorption of Benzene and Toluene

In this work, we determined the surface characteristics of natural (CA-1) and HNO3 treated (CA-2) CAG. Equilibrium, kinetics and breakthrough for adsorption of benzene and toluene by CA-1 and CA-2 were studied. Concentrations of benzene and toluene (mg/L) were determined by gas chromatography with headspace extraction. The data of adsorption kinetic and equilibrium were best fitted by pseudo-second order model and Langmuir isotherm, respectively. The best results of benzene and toluene adsorption from fixed bed were obtained at volumetric flow rate (Q1 = 70 mL/min) using adsorbent CA-2. The study of inferential statistics revealed that CA-1 and CA-2 adsorbents are statistically different at a 5% significance level.

Peanut Shell Activated Carbon： Characterization, Surface Modification and Adsorption of Pb^2＋ from Aqueous Solution

特别与象铅那样的重金属离子，饮用水和废水的金属离子污染是一个严重、进行中的问题。在这个工作，从花生壳(PAC ) 准备的活性炭从水溶液被用于 Pb^(2+) 的移动。修改酸的碳的 Pb2 吸附能力的影响与 HNO3 氧化了也被调查。PAC 的表面官能团被 Fourier 变换证实红外线(FTTR ) 光谱学， X 射线光电子能谱法(XPS ) ， Boehm 滴定。组织上性质(表面积，全部的毛孔体积)在介绍的试验性的结果显示了的 77 K.The 从氮吸附等温线被评估吸附数据与商业颗粒活性炭(粒状活性炭)与兰米尔吸附 model.A 比较级学习更好适合，这证明 PAC 基于兰米尔是与粒状活性炭相比更有效的 10.3 次最大的吸附能力。由兰米尔方程的进一步的分析结果显示出那 HNO3 [20%( 由质量)] 修改 PAC 从水溶液有 Pb^(2+) 的更大的吸附能力(差不多 35.5 mg · g ^(-1)) 。归功于到毛孔拓宽的吸附能力改进，由氧组的增加的阳离子交换能力，和碳的支持的 hydrophilicity 出现。

Effect of surface modification of activated carbon on its adsorption capacity for NH_3

To investigate the effects of carbon surface characteristics on NH3 adsorption,coal-based and coconut shell activated carbons were modified by treatment with oxidants.The surface properties of the carbons were characterized by low temperature nitrogen sorption,by Boehm's titrations and by XPS techniques.NH3 adsorption isotherms of the original and the modified carbons were determined.The results show that the carbons were oxidized by HNO3 and(NH4)2S2O8,and that there was an increase in oxygen containing functional groups on the surface.However,the pore-size distribution of the coal-based carbons was changed after KMnO4 treatment.It was found that the NH3 adsorption capacity of the modified carbons was enhanced and that the most pronounced enhancement results from(NH4)2S2O8 oxidation.Under our experimental conditions,the capacity is positively cor- rected to the number of surface functional groups containing oxygen,and to the number of micro-pores.Furthermore,an empirical model of the relationship between NH3 adsorption and multiple factors on the carbon surface was fit using a complex regression method.

High adsorption of Cd(Ⅱ)by modification of synthetic zeolites Y,A and mordenite with thiourea

Zeolites Y,A and mordenite(ZY,ZA and ZM)were obtained from diatomite in a template-free system,and the products were modified by thiourea(TU).Characterization studies results indicated that the TU molecules were loaded onto the exterior surfaces of the synthetic zeolites as well as the channels.Elemental analysis and energy-dispersive X-ray spectrometer proved that the TU molecules loaded on to ZA were more than ZY and ZM.Removal of Cd(Ⅱ)was investigated,and itwas found that themodified zeolites have higher removal capacity,modified ZA is especially noticeable.In the adsorption experiments,the effects of various parameters such as sorbent content,contact time,concentration of cadmium solution,pH,selectivity and regeneration were discussed.At the best removal efficiency by modified zeolites,the maximum adsorption capacity is 94.3 mg·g^−1,103.2 mg·g^−1 and 89.7 mg·g^−1 at 25℃,respectively.The sorbents show good efficiency for the removal of Cd(Ⅱ)in the presence of different multivalent cations and have good regeneration effect.For the modified samples,removal experiments take place via ion exchange and complexation processes.

Characterization and Modification of a Clay Mineral Used in Adsorption Tests

Clay minerals are widespread in natural systems and have been widely used for the removal of pollutants. In this study, natural expanded vermiculite was used in adsorption tests to remove ammonium nitrogen from landfill leachate. The modification of vermiculite was carried out using NaOH and HCl, and for both modifications the best concentration was 0.1 mol/L. The results produced by XRD (X-ray diffraction) showed that Al replaced K after modification of the vermiculite using HCl and that Mg and Na replaced K after modification using NaOH. It was observed that the adsorption capacity increased as the percentage in mass of K diminished. The Langmuir is the isotherm that presents the best fit of the data, and the values of RL (the Langmuir coefficient) suggest that the adsorption is linear. The thermodynamic parameters indicate that the process is spontaneous and endothermic, that there is a high affinity between the adsorbate and the adsorbent, and that physical adsorption is prevalent.

Lysozyme adsorption to cation exchanger derivatized by sequential modification of poly(ethylenimine)-Sepharose with succinic anhydride and ethanolamine: Effect of p H and ionic strength

In our previous work, a series of polyethylenimine(PEI)-derived cation exchangers were synthesized using PEIgrafted resin FF-PEI-L740(ionic capacity, 740 mmol·L^-1) as the basic resin to study lysozyme adsorption and chromatographic behavior. It was found that the resin with an ionic capacity of 630 mmol·L^-1(FF-PEI-CR630)possessed high adsorption performance towards lysozyme at 0–100 mmol·L^-1 Na Cl. Therefore, in this work,FF-PEI-CR630 was selected to study the influences of pH and ionic strength(IS) on protein adsorption and chromatographic behavior towards lysozyme. The increase of lysozyme adsorption capacity in the pH range of 6 to 10 was observed. However, the uptake rate decreased in the pH range of 6 to 8 and then remained essentially unchanged from pH 8 to pH 10. Increasing IS led to decreased protein adsorption capacity and increased uptake rate in different pH ranges. Besides, FF-PEI-CR630 maintained dynamic binding capacity as high as over150 mg·ml^-1 at pH 8–10 without NaCl. The research has thus provided insight into the selection of proper pH and IS conditions for protein purification by using FF-PEI-CR630.

Comparison and Analysis of Toluene Adsorption Properties of ZSM-5 Molecular Sieve Treated by Different Modification Methods: Adsorption Kinetic and Mechanism Studies

MFI molecular sieve with high specific surface area,adjustable pore size and low production cost have been recognized as an effective adsorbent for VOCs removal.In this paper,NaOH solution was used to etch ZSM-5 to increase specific surface area and micro-mesoporous content.Graphene oxide(GO)was loaded on ZSM-5 by ultrasonic-assisted heating immersion method,and largeπ-bond structure and oxygen-containing functional groups were added to ZSM-5 for improving the composite adsorption performance.In addition,the properties of OH-ZSM-5 and ZSM-5@GO composites for toluene adsorption under different factors were also studied.It was positively correlated with initial concentration and adsorbent mass,but was negatively correlated with temperature.Meanwhile,the results showed that the saturated adsorption capacity of OH-ZSM-5(107.3 mg/g)was 1.34 times higher than that of ZG-15%(80.2 mg/g).The pseudo-first-order and pseudo-second-order kinetic model can well describe the adsorption behavior of toluene on the OH-ZSM-5 and ZG-15%,respectively.The adsorption mechanism of OH-ZSM-5 was mainly pore-filled adsorption.However,the adsorption mechanisms of ZSM-5@GO composite were pore-filled adsorption,π-πinteraction,and H-bond interaction.This study will help to design a new strategy for enhancing the performance of traditional adsorbent ZSM-5 in VOCs removal.

MODIFICATION OF X-5 RESIN AND ADSORPTION PROPERTY OF THE MODIFIED RESINS

Three polymeric adsorbents with hydrogen bonding acceptors, methylamine, N-methyl-acetamide and aminotri(hydroxymethyl)methane modified resins are synthesized from chloromethylated X-5 resin. Adsorption isotherms of phenol and theophylline onto the three modified resins and the original X-5 resin from aqueous solution are measured. The results show that adsorption of compounds with hydrogen bonding donor onto methylamine and N-methylacetamide modified resins is enhanced as compared with that onto X-5 resin, and adsorption mechanism between the adsorbents and the adsorbates is mainly based on hydrogen bonding and hydrophobic interaction. While adsorption of compounds with hydrogen bonding donor onto aminotri(hydroxymethyl)methane modified resin is lowered as compared with that onto X-5 resin, and adsorption mechanism between the adsorbent and the adsorbates is mainly based on hydrophobic interaction.

Succinylation modification:a potential therapeutic target in stroke

Stroke is a leading cause of mortality and disability worldwide.Ischemic cell death triggered by the compromised supply of blood oxygen and glucose is one of the major pathophysiology of strokeinduced brain injury.Impaired mitochondrial energy metabolism is observed minutes after stroke and is closely associated with the progression of neuropathology.Recently,a new type of posttranslational modification,known as lysine succinylation,has been recognized to play a significant role in mitochondrial energy metabolism after ischemia.However,the role of succinylation modification in cell metabolism after stroke and its regulation are not well understood.We aimed to review the effects of succinylation on energy metabolism,reactive oxygen species generation,and neuroinflammation,as well as Sirtuin 5 mediated desuccinylation after stroke.We also highlight the potential of targeting succinylation/desuccinylation as a promising strategy for the treatment of stroke.The succinylation level is dynamically regulated by the nonenzymatic or enzymatic transfer of a succinyl group to a protein on lysine residues and the removal of succinyl catalyzed by desuccinylases.Mounting evidence has suggested that succinylation can regulate the metabolic pathway through modulating the activity or stability of metabolic enzymes.Sirtuins,especially Sirtuin 5,are characterized for their desuccinylation activity and have been recognized as a critical regulator of metabolism through desuccinylating numerous metabolic enzymes.Imbalance between succinylation and desuccinylation has been implicated in the pathophysiology of stroke.Pharmacological agents that enhance the activity of Sirtuin 5 have been employed to promote desuccinylation and improve mitochondrial metabolism,and neuroprotective effects of these agents have been observed in experimental stroke studies.However,their therapeutic efficacy in stroke patients should be validated.

Surface modification of coconut-based activated carbon by SDS and its effects on Pb^(2+) adsorption

Coconut-based activated carbons were modified with sodium dodecyl sulfate (SDS). The activated carbons, which were modified by different concentrations of SDS, were characterized by acid/base titrations, textural analysis (BET), atomic absorption spectrochemical analysis and Zeta potential measurements. The effects of SDS modification on Pb2+ absorption were studied further. The results indicate that after the modification of SDS, there are new functional groups on the surface of modified activated carbons and the number of functional group has changed remarkably, the total acidity decreases observably, but the total alkalinity increases dramatically. With the increase of surface load with SDS, the Pb2+ adsorption mass of activated carbons increases and the optimal pH for Pb2+ adsorption of the SDS modified activated carbons is 5. The experimental data are simulated better by Freundlich isotherm model for the modified activated carbons, and the experimental data are simulated better by Langmuir isotherm model for unmodified ones.

MODIFICATION OF TRYPTOPHAN RESIDUES OF IgGRF AND ITS EFFECT ON THE ADSORPTION CAPACITY

Tryptophan residues of IgGRF from rheumatoid arthritis patient were modified with N-Bromosuccinimide (NBS) and the product of modification was characterized by UV-spectrum、Fluorescence emission spectrum and CD-spectrum. The corresponding adsorption capacity of immobilized ssDNA immunoadsorbent for IgGRF was enhanced from 46% to 86%, This result indicates the tryptophan residue is essential for the interaction between ssDNA and IgGRF .and ionic-bonding plays an important role in adsorption.