adsorption

摘要： The world wide application of dyes in papermaking, fabric, lithography, leather and other industrial production, has attracted more attention, due to water pollution caused by these organic dyes. Metal-organic frameworks (MOFs) which are a physical adsorption method of wastewater treatment are a kind of special three-dimensional crystal-like constituents built by multipurpose ligands and metallic ion classes, showing an advantage in removal of pollutants from solutions because of its unique properties are convenient for operation, high removal efficiency, and low cost. In this study, we investigated Fe-Mg based metal organic framework, Fe-Mg MOFs which was directly synthesized by the hydrothermal method. The obtained materials were analyzed with XRD, FT-IR, TG-DTG, SEM etc. and used for the treatment of printing and dyeing wastewater. The results showed that it has good adsorption performance for cation dye rhodamine B (RhB) and anion dye methyl orange (MO) in a wide pH range. The Fe-Mg MOF even after the 4th run, the Fe-Mg MOF catalyst still maintained nearly the initial catalytic activities. The kinetic studies revealed the adsorption process of the both contaminants obeys a pseudo-second order model. In addition, the equilibrium adsorption data of RhB and MO are in good agreement with Langmuir models. The maximum adsorption capacities are 694.44 and 236.97 mg/g at 308 K respectively. This work synthesizes a promising dual-functional adsorbent that can remove cationic and anionic dyes, which provide potential applications for actual wastewater treatment.

摘要： Removing impurities such as carbon dioxide and nitrogen from natural gas is a technical challenge and one of the major concerns in natural gas treatment process.In this study,adsorption of CH_(4),N_(2),and CO_(2)on the Faujasite(FAU)zeolite has been studied using molecular dynamics simulation at temperatures of 293,308,and 323 K and pressures up to 1 MPa.COMPASS force field was used to model the interactions between zeolite and guest molecules.Ewald and atom-based summation methods were used for the calculation of electrostatic and van der Waals forces,respectively.Simulated results were modeled using Langmuir,Freundlich,Toth,and Sips adsorption isotherms.Sips isotherm for CO_(2),and Toth isotherm for CH_(4)and N_(2)pure compounds showed the best performance.Heat of adsorption for CH_(4),CO_(2),and N_(2)were calculated to be-15.48,-24.1,and-13.31 kJ·mol^(-1),respectively.A comparative study showed that the simulation model was successful in predicting the overall trend of the adsorption with acceptable accuracy.

摘要： Ultra-deep desulfurization of transformer oil is of great demand among power industry.In this work,the effective and deep removal of various types of organosulfurs,including mercaptan,sulfide and disulfide via catalytic adsorptive desulfurization(CADS)using bifunctional Ti-based adsorbent is reported.Compared to adsorptive desulfurization(ADS),dramatically improvement of the organosulfur uptakes were achieved under CADS process.The equilibrium adsorption capacity at 5 μg∙g^(-1) S reached up to 15.7,33.4,11.6 and 11.9 mg∙g^(-1) for propyl mercaptan(n-PM),dimethyl sulfide(DMS),di-t-butyl disulfide(DTBDS)and dibenzyl disulfide(DBDS),which was 262,477,97 and 128 times to that of ADS process,respectively,and was the highest among the reported desulfurization adsorbents.Moreover,it achieved superior breakthrough capacity of 2050,530 and 210 ml F·(g A)^(-1) at the breakthrough S concentration of 1 μg∙g^(-1) of the commercial transformer oil S containing 10,50 and 150 μg∙g^(-1),respectively.The effectiveness of CADS is associated to the transformation of sulfur species to higher polar sulfonic species with the assistance of mild oxidant,which can be readily captured by silanol groups on SiO2 through Hbonding interaction.The excellent recyclability of the adsorbent can be realized through solvent washing or oxidative air treatment.This work provides an effective and economic approach for the elimination of trace amount of mercaptan,sulfide and disulfide from transformer oil.

摘要： Metal-organic frameworks(MOFs)have great potentials as adsorbents for natural gas purification.However,the trade-off between selectivity and adsorption capacity remains a challenge.Herein,we report a pillared-layer metal-organic framework Ni(HBTC)(bipy)for efficiently separating the C_(3)H_(8)/C_(2)H_(6)/CH_(4) mixture.The experimental results show that the adsorption capacity of C_(3)H_(8) and C_(2)H_(6) on Ni(HBTC)(bipy)are as high as 6.18 and 5.85 mmol·g^(-1),while only 0.93 mmol·g^(-1) for CH_(4) at 298 K and 100 kPa.Especially,the adsorption capacity of C_(3)H_(8) at 5 kPa can reach an unprecedented 4.52 mmol·g^(-1) and for C_(2)H_(6) it is 1.48 mmol·g^(-1) at 10 kPa.The ideal adsorbed solution theory predicted C_(3)H_(8)/CH_(4) selectivity is as high as 1857.0,superior to most of the reported materials.Breakthrough experiment results indicated that material could completely separate the C_(3)H_(8)/C_(2)H_(6)/CH_(4) mixture.Therefore,Ni(HBTC)(bipy)is a promising material for separation of natural gas.

摘要： MXenes have attracted increasing research enthusiasm owing to their unique physical and chemical properties.Although MXenes exhibit exciting potential in cations adsorption due to their unique surface groups,the adsorption capacity is limited by the low specific surface area and undeveloped porosity.Our work aims at enhancing the adsorption performance of a well-known MXene,Ti3C2Tx,for methylene blue(MB)by decorating tiny ZIF-8 nanoparticles in the interlayer.After the incorporation of ZIF-8,suitable interspace in the layers resulting from the distribution of tiny ZIF-8 appears.When employing in MB,the adsorption capacity of composites can reach up to 107 mg·g^(-1) while both ZIF-8(3 mg·g^(-1))and Ti_(3)C_(2)Tx(9mg·g^(-1))show nearly no adsorption capacity.The adsorption mechanism was explored,and the good adsorption capacity is caused by the synergistic effect of ZIF-8 and Ti_(3)C_(2)Tx,for neither of them is of suitable interspace or surface groups for MB adsorption.Our work might pave the way for constructing functional materials based on the introduction of nanoparticles into layered materials for various adsorption applications.

摘要： The separation of light hydrocarbon mixtures(C_(1)–C_(3))generated from petrochemical industry is vital and challenging process for obtaining valuable pure chemical feedstocks.In comparison to the energy intensive conventional separation technologies(cryogenic distillation,absorption and hydrogenation),the adsorptive separation is considered as a low energy cost and high efficiency process.Porous carbons have been demonstrated as excellent adsorbents for the separation of light hydrocarbons,owing to their designable structure and tailorable properties.This review summarizes the recent advances of using porous carbons as adsorbents for the separation of light hydrocarbons,including methane/nitrogen,methane/alkane,methane/carbon dioxide,ethylene/ethane and propylene/propane.We discuss the separation mechanisms and highlight the material features including pore structure,surface chemistry and target molecular properties that determine the separation performance.Furthermore,the challenges and development direction associated with carbonaceous adsorbents for light hydrocarbon separation are discussed,meanwhile the guidelines for the design of porous carbons are proposed.

摘要： Aerogel composed of polyaniline/cellulose nanofiber(PANI/CNF)was synthesized by a two-step method and used as an adsorbent to remove Cr(Ⅵ)from wastewater in this study.Adsorption results showed that PANI/CNF aerogel adsorbent exhibited a high adsorption capacity of 298.5 mg·g-1 for Cr(Ⅵ)(318 K,pH=2.0).Meanwhile,the adsorption process can be fitted well with the pseudo-second-order model and the Freundlich model.Moreover,the Cr(Ⅵ)removal efficiency of the adsorbent remained above 85%after ten recycling experiments,indicating that PANI/CNF aerogel had excellent stability and reusability.Therefore,PANI/CNF aerogel showed a potential application in the treatment of chromium-containing wastewater.

摘要： Many solid adsorbents have been prepared for the CO_(2)capture.In particular,the photoresponsive adsorbents have attracted extensive interests because of their tunable pore structure and variable responsive behaviors provoked by the external light.However,it is challenging to fabricate the photoresponsive adsorbents featured the big CO_(2)capacity and high CO_(2)selectivity.Herein,copolymerized between 4-phenylazobenzoyl chloride,2,4,6-trichloro-1,3,5-triazine and melamine,a series of azobenzenefunctionalized porous polymers(PTM-AZOs)are successfully synthesized.The PTM-AZOs are verified in possession of proper pore structures,large surface area and photoconductive properties through a series of characterization.The PTM-AZO-2 with the trans-isomerization exhibits the best CO_(2)adsorption amount of 2.7 mmol·g^(-1)(273 K and 0.1 MPa),while the CO_(2)/N_(2)selectivity can reach 2459 and 607 on the trans-and cis-isomerization,respectively.The regulatable pore structures controlled by the photoresponsive azobenzene groups affect the CO_(2)capture performance of the PTM-AZOs.

摘要： Large amounts of solid wastes and flue gases are generated in iron and steel production process,probably leading to serious environmental pollution without duly handle.An innovative and green process of simultaneous reduction of zinc-bearing dusts and activation of low-rank coal was developed and its mechanism was clarified in this paper.Under the optimal conditions,the reduced zinc-bearing dusts containing low harmful elements(0.02%Zn,0.015%K and 0.03%Na)could be made as high-quality burden for blast furnace while the low-rank coal was transferred into K,Na-embedded activated carbon,which can be used as effective adsorbent for purification of SO_(2) and NO-containing flue gases.The solid wastes were successfully utilized to treat the flue gases through the process.The synergetic activation and reduction mechanism in the process was revealed.The coupling effect between reduction reactions of metal oxides in the dusts and activation reaction of carbon in the coal promoted the simultaneous reduction and activation process.In the meanwhile,part of the potassium and sodium from the zinc-bearing dusts could be adsorbed by the activated carbon and played a catalytic role in the activation process.

摘要： It is of significance to investigate deeply the hydrodynamic featu res of the bubble co ntaminated by impurities in view of the fact that the industrial liquid is difficult to keep absolutely pure.On the basis of the finite volume method,the bubble interface contaminated by the surfactant(1-pentanol)is achieved through solving the concentration transport equations in liquid and along the bubble interface,and solving the absorption and desorption equation at the bubble interface.And the three-dimensional momentum equation is solved at the same time.It is investigated in detail on the influence of interfacial contamination degrees(described with the cap angleθ)on hydrodynamic characteristics of the spherical bubble when the bubble Reynolds number(Re)is larger than 200.Theθis realized by changing the surfactant concentration(C_(0)) in liquid.The present results show that the hydrodynamic characteristics,such as interfacial concentration,interfacial shear stress,interfacial velocity and wake flow,are related to both Re and C_(0) for the contaminated bubble.When C_(0) is relatively low in liquid(i.e.,the contamination degree of the bubble interface is relatively slight),the hydrodynamic characteristics of the bubble can still keep the 2 D features even if Re>200.The decrease ofθor the increase of Re can promote the appearance of the unsteady wake flow.For the present investigation,when Re>200 andθ≤60°,the hydrodynamic characteristics of the bubble show the 3D phenomena,which indicates that axisymmetric model is no longer valid.

摘要： In this paper, we studied the efficiency of the synthetic organo-red soil (OS) modified with threesurfactants (Cetyltrimethylammonium Bromide (CTMAB), Sodium Dodecyl Benzenesulfonate (SDBS) andPolyethylene Glycol-4000 (PEG-4000)) for the removal of the p,p’-dichlorodiphenyldichloroethylene(p,p’-DDE) from contaminated water. The results demonstrated that the adsorption behavior dependedgreatly on the type and concentration of surfactant and the hydrophobic properties of the pesticides.Examination using BET surface area and TOC measurements revealed that surfactants increased the surfacearea of OS and replaced hydrophobic with hydrophilic on the OS surface. The adsorption efficiency of redsoil for the pesticides followed the order：OSY>OSF>OSYI>OSN. According to the value of R2, it can beconcluded that the best fit for the experimental adsorption data were given by the Redlich-Peterson modeland homogeneous particle diffusion model.

摘要： Adsorption refrigeration is a kind of environmental friendly green refrigeration technology. Its major superiority is the capability of using low-grade thermal energy and environmental protection. In this thesis,the heat and mass transfer performances and thermody namic mechanism of solid adsorption refrigerating system using active carbon-ammonia as working pairs were investigated. The mathematic model for the dynamrcoperation of the heat transfer was built.The no dimensional heat transfer equation was solved by using finitedifference method and the calculation program of the model was made by using programming language-Matlab.

摘要： In this paper, titanate nanotubes were synthesized with hydrothermal treatment of the commercialTiO2particles (Aldrich,≥99%purity, 325 mesh). The morphology and structures of as-prepared samples wereinvestigated by transmission electron microscopy (TEM), X-ray diffraction (XRD) and N2adsorption/desorption. The samples exhibited a tubular structure and a high surface area of 155.78 m2g-1.Batch experiments showed that the adsorption of tetracycline hydrochloride (labeled as TC) was preferred inweak acid solution. The amount of equilibrium adsorption increased with the increasing initial TCconcentration, while decreased with the increasing TNTs dosage. The adsorption kinetics was also evaluatedby the pseudo-first-order and pseudo-second-order. The pseudo-second-order model was the best to describethe adsorption kinetics. The equilibrium adsorption data were analyzed with two isotherm models (Langmuirmodel and Freundlich model). The best agreement was achieved by the Langmuir isotherm with correlationcoefficient of 0.997, corresponding to maximum adsorption capacity of 111.1 mg g-1.

摘要： In this study, KOH dry etching was explored to prepare activated multi-walled carbon nanotube(MWCNTs) for adsorption of four model priority pollutants namely ethylbenzene, p-xylene, m-xylene ando-xylene (EX) in an aqueous solution. With KOH activation with three different ratios, the total surface areawas increased from 123.5m2/g to 190, 456.6 and 534.6 m2/g for activated MWCNTs, respectively, andsubstantial pore volumes were created for the activated samples. Consistently, adsorption of four modeladsorbates was enhanced 3-4 times on CNTs-K6. The results indicated that Langmuir model is more suitableto simulate the EX adsorption isotherms than Freundlich and Dubinin-Radushkevich model. The trend of qe is strongly correlate with total surface area of MWCNTs. This suggests that changes in equilibriumadsorption capacity upon activation are principally caused by changes in pore structure, notably surface area.The results highlight the important role of pore structure and surface area in controlling the adsorptionproperties of EX onto MWCNTs in wastewater treatment. This is the first study on the adsorption of EX inaqueous solutions by KOH-activated carbon nanotubes. The findings indicate that KOH etching is a usefulactivation method to improve the adsorption affinity of monoaromatic hydrocarbons on carbon nanotubes.

摘要： The eclectic occurrence of microcystins (MCs) produced by freshwater cyanobacteria (blue-greenalgae) has increasingly become an environmental and health concern worldwide, which led to an intensivesearch of various techniques for their removal from waters. Adsorption is an effective method for the removalof MCs and the efficiency of MCs adsorption related to mesoporosity due to MCs contains large moleculardimensions (1.9×1.1×1.5nm3) in previous studies. In this paper, mesoporous silica materials (MSM) withdifferent mesostructure and pore size are prepared as adsorbents, such as SBA-15 with two-dimensionally (2-D)hexagonally mesostructure (p6mm) and 6.5, 7.8, 10.2nm, MCM-41 (p6mm, 2.8nm), and KIT-6 (3-Dbicontinuous cubic, Ia3d, 12.7nm). We demonstrate that the larger pore size (10nm) and p6mm mesostructurecould be more favorable for mass transformation. SBA-15-130 shows the best adsorption capacity of 98%MCLR and 78%MCRR. Batch equilibrium adsorption experiments performed at different pH values bySBA-15 shows the better adsorption capacities range between 3 and 6 for MCLR, between 2 and 4 for MCRR.The mechanisms during the adsorption process by MSM are also studied by kinetic and equilibrium adsorptiondata analysis, with 344.12mg/g--the maximum adsorption capacity, as predicted by Langmuir isotherm.