The efficient removal of perfluorooctanoic acid (PFOA) from contaminated water remains a challenge due to the very stable carbon?fluorine bonds in perfluorinated compounds.In this experiment,nanosecond pulsed dielectric barrier discharge (DBD) plasma was used to degrade PFOA,a difficult?to?degrade organic pollutant in water,and the effects of discharge parameters such as discharge atmosphere,discharge power,gas flow rate,and liquid flow rate,as well as the reaction conditions,on the removal rate of PFOA were investigated in the reaction.The experimental results showed that under the conditions of the discharge atmosphere of argon,discharge power of 11.84 W,gas flow rate of 3.33 L/min,and liquid flow rate of 0.28 L/min,DBD had a better degradation effect on PFOA,and the removal rate could reach more than 94.0% after 60 min of reaction.Combined with emission spectroscopy and free radical burst analysis,it was determined that e-,?OH,H2O2, and O3 were the main active species to break the molecular structure of PFOA and realize the efficient degradation of the reactants,and thus could provide an effective solution for the removal of PFOA in water.
Anthraquinone dyes are the second most significant dyes in the dye industry after azo dyes.Nitroanthraquinone prepared by the nitration of anthraquinone,is one of the important raw materials for the synthesis of various types of anthraquinone dyes.In this study,a microreactor with excellent heat and mass transfer properties was utilized to investigate the continuous?flow nitration process of anthraquinone.The effects of key process parameters such as reaction temperature,volume flow rate,molar ratio of nitric acid to anthraquinone,anthraquinone concentration,residence time,and sulfuric acid intensity on the nitration process were examined.The results showed that the competition between mono? and di?nitrification reactions during anthraquinone nitrification was significant, and the adjustment of process parameters would significantly affect the ratio of mono? and di?nitrification products while promoting the conversion rate of anthraquinone.The full use of the advantages of microreactors to precisely regulate the process parameters is an effective measure to improve the selectivity of the target nitration product.
Plastics are synthetic or natural polymers that are widely used in industrial fields and daily life due to its good durability and plasticity.Among plastics,polyethylene terephthalate (PET) is the most commonly used.Polyethylene terephthalate (PET) is one of the commonly used plastics,which is widely used in many fields.PET is difficult to be degraded under natural circumstances without artificial treatment,which brings serious burden to the ecosystems,so the issue of degradation and regeneration of PET plastics has become a hot issue globally.Many methods such as photodegradation,thermal degradation,biodegradation,etc.,have been developed to degrade plastics.Among them,biodegradation is considered as environmental friendly and highly efficient method.Thus,the design and transformation of PET degradation has become a key issue.The main methods for degrading plastics at the present stage,the common enzymes used for degrading PET by biodegradation methods and the modification methods of PET degrading enzymes are reviewed,to provide a theoretical basis for the rapid degradation and regeneration of PET.
Aiming at the problems of slow generation rate,low storage capacity and harsh generation conditions of CO2 during the hydrate generation process,bimetallic Cu and Al?loaded graphene oxide materials were used as additives for the kinetic characterisation of CO2 hydrate generation.Firstly,the prepared GO?Cu?Al material was characterized by TEM,EDS,XPS,and stability analysis.Secondly,experiments were conducted on the kinetics of CO2 hydrate formation under 274.15 K and 3.0 MPa.The effects of different additive concentrations on the induction time,reaction time, gas consumption,and gas storage capacity of CO2 hydrate formation were analyzed,and a comparison was made between monometallic and bimetallic supported materials.The results show that bimetallic Cu and Al can be uniformly loaded onto graphene oxide with good stability.At 274.15 K,3.0 MPa,and a concentration of 50
Cobalt?based catalyst is regarded as a suitable choice for Fischer?Tropsch synthesis (FTS) due to its high activity and strong C—C bond formation ability. FTS reaction mechanism of Co?based catalysts was summarised, and the structure of the active phase as well as the conformational relationship between additives and catalytic performance were analysed. For clarifying the role of catalyst supports, the promotion of FTS reaction via regulating metal?carrier interaction was also summarized. Specially, the direct synthesis of liquid fuel by coupling metal Co with zeolite catalyst was discussed, and the reaction route for liquid fuel and the character of as?used bifunctional catalyst were focused.
Graphite phase carbon nitride(g?C3N4), as an environmentally benign semiconductor material, has good application prospects in photocatalysis. However, the disadvantages of pure g?C3N4 such as small specific surface area and difficult separation of photogenerated carriers will limit its photocatalytic performance, which will restrict its large?scale application.From the synthetic methods and modification strategies, the research progress of g?C3N4 photocatalysts by researchers in recent years is reviewed, and the development of g?C3N4 photocatalysts in the fields of degradation of pollutants in water treatment, H2 and H2O2 production is summarised, and it can be found that the performance of the modified g?C3N4 photocatalysts has been greatly improved.Finally,the development direction of g?C3N4 photocatalyst is prospected.
Aerogel is a solid material with the smallest density and lightest weight in the world at present. Its unique three?dimensional network structure makes it widely used. Cellulose aerogels not only have the characteristics of high porosity and high specific surface area of aerogels, but also can be degraded by microorganisms and be compatible with other substances, which is a new energy suitable for sustainable development. The preparation process of cellulose aerogel—sol gel process and hydrogel drying process are described. In addition, the applications of cellulose aerogel in oil?water separation, heat insulation, phase change, supercapacitor, biomedicine and other aspects are also introduced, and its development is prospected.
In order to achieve high ionic conductivity and good alkaline resistance of Polysulfone?based AEMs, chloromethylated polysulfone was prepared by green method, and crown ether?functionalized polysulfone membranes with different triethylamine and amino crown ether contents were then prepared using amino crown ether as cross?linking agent and metal ions and triethylamine as cationic groups followed by crown ether functional polysulfone membrane with triethylamine and triethylamine as cationic groups(PSF?CE X ?QA1?X ).The effect of the addition of polyethylene glycol on the membrane properties was explored by introducing the low molecular weight polyethylene glycol (PEG) into the above polysulfone cross?linking membrane.The results shown that the presence of hydrophilic polyethylene glycol helps to facilitate the formation of ordered ion channels in the membrane.The conductivity and alkali?resistant stability of PSF?CE X ?QA1?X ?PEG were improved compared to PSF?CE X ?QA1?X membrane.Among them, the electrical conductivity of PSF?CE0.1?QA0.9?PEG at 80 ℃ is 56.78 mS/cm,which can retain 85% of the original conductivity after alkaline resistance test.In addition,PSF?CE X ?QA1?X ?PEG has good dimensional and thermal stability.
The modification of waterborne polyurethane(WPU) coating can be improved, and the nanocomposite particles can be added to WPU coating, and its mechanical properties and ultraviolet resistance can be improved.GO was synthesized by modified Hummers method, nano?ZnO/CeO2 by copprecipitation, and nano?GO?ZnO/CeO2 by in situ polymerization.It was also characterised by FT?IR,TEM,SEM,XRD,etc.,and the effect of nano?GO?ZnO/CeO2 doping on the performance of WPU was explored.The results showed that nano?GO?ZnO/CeO2 was composed of hybrid particles formed by ZnO and CeO2 of cubic crystal fluorite structure on the GO surface. Compared with the pure WPU film,the fracture tensile strength and elongation at break of the WPU film with the addition of a mass fraction of 0.6% nano?GO?ZnO/CeO2 increased by 43.1% and 47.0%.After 168 h of UV aging experiments,the modified membrane absorbed 15.4% of water,increased the tensile strength at break by 328.0% and the elongation at break by 39.0%.It shows that nano?GO?ZnO/CeO2 can effectively improve the mechanical properties and UV aging resistance of WPU after film formation.
Surface?enhanced Raman spectroscopy (SERS) is an important spectroscopic method with the advantages of high sensitivity, simplicity, fast detection and good selectivity. The performance of SERS is highly dependent on the properties of the enhanced substrate. Cellulose is one kind of the most abundant biopolymer in the world, which is inexpensive, readily available, renewable and environmental friendly. Therefore, cellulosic materials are usually employed to prepare SERS substrate. In this review, the enhancement mechanism of SERS was firstly disscussed, and then the fabrication of cellulose SERS substrates were introduced. The applications of cellulose SERS substrates were reviewed in biological analysis, water quality assessment, food safety and environmental pollution, and dye identification.
