Liquid-continuous impinging streams（LIS）have the excellent features of enhancing micromixing，strong pressure fluctuation and promoting process kinetics，which are extremely valuable for processes occurring on molecular scale. The authors investigated these features；and also studied the preparation of several“ultrafine”and nano materials experimentally by reaction-precipitation in LIS，and obtained products of smaller particles with narrower size distribution and controlled appearance. Several devices employing LIS for reaction and crystallization have been developed and applied，and the flow configuration，working principles and industrial application status of such devices are described.

Membrane，as a modern effective chemical separation technology，has been applied in a number of industries for 20 years. Researchers are recently studying a new way of substance characterization by membrane gradient separation. Membrane gradient separation achievements abroad are used in separation of ultra colloid，quantitative analysis of readily biodegradable substances，determination of the relationship between chemical oxygen demand and size distribution of pollutants，and biodegradable ability evaluation. In China，exploratory work presently focuses on molecular weight distribution of source water，pollutants characterization of landfill leachate and water quality analysis of coagulation effluent.

The integrated separation technology which combined extractive distillation and urging fractionation was used to separate mesitylene from C₉ arene. The effects of number of theoretical plate，reflux ratio and extractant/feed/urging solvent ratio（mass fraction）on the purity of mesitylene product from top and bottom of composite separation tower were investigated. Mesitylene product of purity over 98.0% was obtained. The number of optimal theoretical plate was 102. Optimal reflux ratio was 15. Optimal extractant/feed/urging solvent ratio was 7∶1∶0.3. The study could provide a basis for further pilot plant test.

The paper introduces the basic principle of oxygen transfer in wastewater treatment，and the relative merits of several types of traditional aeration equipment，and presents a new increasing oxygen aeration equipment，screw aeration equipment. The aeration performance of the equipment was investigated. The test result showed that the aeration equipment had good aeration performance，good oxygenation capacity，high oxygen utilization efficiency over 30%，easy installation，and could be widely used in wastewater treatment process of refining/petrochemical/chemical industries.

Demetallation of asphaltene was studied. The methods of single phase complexation extraction，water washing under ultrasonic irradiation，and single phase complexation extraction under ultrasonic irradiation were compared. The metals studied included nickel and calcium. The result revealed that ultrasonic irradiation was helpful for demetallation. Furthermore，these processes were effective in removing calcium，but not so prominent for removing nickel. The result indicated that calcium and nickel existed differently in asphaltene. Nickel was firmly fixed，but calcium was loose.

A rotary retorting reactor was designed and built for studying the mixing behavior of particulate oil shale and granular solid heat carrier. The sample coefficient of variation（cv，%）of mass percent of oil shale at the rotary retorting outflow was taken as mixing index. Mixing index was calculated at different work conditions（2 percentages of vessel filling，2 types of lifting flight，2 vessel dip angles and 5 different rotating speeds）. Comparison and analysis the variation trend of mixing index and mixing mechanism showed that the mixing degree with right-angle lifting flight was better at 20% vessel filling and 3.24°dip angle and convective mixing played a major role.

After an in-depth study of shale oil condensation recovery process，process simulation software PRO/II was used to simulate the process. The simulation results were analyzed，and the process was optimized aiming the shortcomings. Firstly，in the optimized process the amount of circulating water was reduced to 215 000 kg/h，and the energy consumption required for water circulation was also reduced. Secondly，in the optimized process countercurrent washing tower was used instead of cocurrent washing tower and the gas-liquid separator in the original process，so the number of equipment required in the process was reduced. The countercurrent washing tower could reduce the heavy oil components in the top off-gas，which was good for succeeding  equipment and process design.

The effect of emulsifiers on the stability of methanol diesel emulsion fuel was studied. The results showed that for the span80 emulsifiers，the HLB value of the emulsifier was 7—8 at minimum surface tension，and demulsification time was 12—26 h，but when the densities of outer and inner phases of the emulsion were equal，demulsification time was 4 h—11 d. For the oleic acid emulsifiers，the HLB value of the emulsifier was 3—6 at minimum surface tension，and demulsification time was 2—24 h，but when the densities of outer and inner phases were equal，demulsification time was 3 h—4 d.

Platinum nanocatalysts has been widely used in catalysis and electrocatalytic due to its ability to maneuver both oxidation and reduction reactions. In addition to size，the shape of a Pt nanocrystal provides a sensitive knob for tuning its catalytic and electrocatalytic properties. Some factors，such as the reductant，stabilizer，and surfactant，are essential to control the shape of nanoparticles and may affect catalytic activity and selectivity. Nowadays，shape-controlled platinum nanocatalysts has been applied to various reactions，such as hydrogenation，oxidation，Suzuki coupling reaction，etc. Compared to commercially available Pt catalysts，these well-de?ned nanocrystals exhibit greatly enhanced activity and selectivity for those reactions. This review mainly introduces the shape-controlled synthesis of platinum nanocatalysts and its applications in catalytic and electrocatalytic reactions.

The catalytic activity of the catalyst system composed of Cr（Ⅲ）2-ethylhexanoate [Cr（Ⅲ）2-EH]，2,5-dimethylpyrrole（DMP），diphenylphosphinoamine（PNP），triethylaluminium（TEA）and 1,1,2,2-tetrachloethxane in ethylene trimerization and the selectivity for 1-hexene were studied. The results showed that the catalyst system improved the activity and selectivity simultaneously. A catalyst activity exceeding 270 kg/gCr per hour was achieved at 120 ℃ and 5.0 MPa，and the selectivity for 1-hexene was more than 95%. Compared with the single ligand DMP or PNP，the catalyst system with composite ligands combined their respective advantages.

Al-MCM-41 mesoporous molecular sieves were prepared by the azeotropic distillation and ultrasonic dispersive technology using sodium silicate as silica source ，aluminum sulfate as aluminum source and cetyltrimethyl ammonium bromide as structure-directing agent. By using Al-MCM-41 as support，nickel nitrate and diammonium hydrogen phosphate as raw materials，a series of supported Ni₂P catalysts on Al-MCM-41 was prepared via the method of temperature-programmed reduction under ultrasonic oscillation. The catalysts were characterized by FTIR，BET，XRD and SEM. Hydrodesulfurization of thiophene catalyzed by Ni₂P/Al-MCM-41 was carried out in a high pressure autoclave reactor. The experimental results showed that Al-MCM-41 prepared by ultrasonic dispersive technology had a much higher specific surface area，larger pore volume and pore diameter than that prepared by conventional mechanical mixing. The Al-MCM-41 prepared by azeotropic distillation with ultrasonic dispersive technology was also better than that using only ultrasonic dispersive technology. The Ni₂P/Al-MCM-41 catalysts，hydrodesulfurization conversion of thiophene nearly reached 100% at the reaction time 5 h，reaction temperature 548 K，and reaction pressure 3.5 MPa.

The effect of water content and storage material on the moisture and the acid number of 5% biodiesel from cotton seed oil，rubber tree seed oil and Jatropha curcas L. seed oil with 0^# diesel blends was studied. The results showed that moisture and acid number of the B5 blends did not significantly change and could meet the national quality standards with addition of less than 1.0% water after 70 days storage at room temperature. B5 biodiesel-diesel blends can be stored in glass，plastic and steel containers.

With silicon oxide as carrier，a catalyst with ZSM-5 molecular sieve with high ratio of n(SiO₂)/n(Al₂O₃) as the active component was prepared for the preparation of propylene and ethylene from C₄ alkenes by catalytic cracking. The precursors of alkali earth and rare earth metal oxides were used to adjust the acidic property of the catalyst. The catalyst was pretreated with steam for 24 h under these conditions of 600 ℃，atmospheric pressure and water weight hourly space velocity（WHSV）1 h^－1. At 485 ℃，0.1MPa，w(H₂O)∶w(C₄^＝)=0.2/0，WHSV 3 h^－1，as well as at WHSV 10 h^－1 without water dilution，the conversion of C₄ alkenes was more than 65% in a 20 day-long reaction process. The yields of propylene and ethylene were more than 31% and 6%，and the amount of carbon deposition on the catalyst was 1.01% using water as diluent in the reaction system. While the yields of propylene and ethylene were more than 27.5% and 4.6%，and the amount of carbon deposition on the catalyst was 4.71% without using water as diluent. The catalysts were characterized by BET，NH₃-TPD and Py-IR. The results showed that the catalytic activity depended on the amount of B acid of the catalyst.

The catalysts with HgCl₂ supported on different carriers were prepared by impregnation methods and characterized by BET，AFS and EA method. The catalytic performance in acetylene hydrochlorination to vinyl chloride was studied in a packed bed reactor. The causes of catalyst deactivation were dicussed. The results showed that the catalysts with HgCl₂ supported on different carriers were greatly different in both catalytic performance and cause of deactivation. An asphaltene based carbon AC-2 carrier was the best one for the reaction. When HgCl₂ loading was 5%，under the optimal conditions：acetylene GHSV 36 h^－1，140 ℃，n(HCl) ∶n(C₂H₂)= 1.05～1.1，its initial conversion exceeded 99%（higher than activated carbon supported catalysts by 39%），and selectivity was close to 100%，its lifespan was up to 3168 h. The catalytic performance was superior to existing industrial high-mercury catalyst.

CuO-ZnO-Al₂O₃ was prepared by gel-network co-precipitation for synthesizing dimethyl ether from carbon dioxide by hydrogenation and the effects of La，Ce，Co and Zr promoters on catalyst performance were investigated. The results showed that after adding a small amount of Ce，the selectivity of dimethyl ether reached 61.5% and the conversion rate of CO₂ reached 40%.The physical-chemical propertise and catalytic performance of the catalysts were characterization by using BET，XRD，SEM，TPR and H₂-TPD techniques.

2Cu-1Ni/5g-Al₂O₃ catalysts were prepared by the deposition precipitation method for dimethyl ether steam reforming（DME SR）reaction. The effect of the different calcination temperature on catalyst structure and performance was investigated by using Brunauer-Emmett-Teller（BET）method，H₂ temperature-programmed reduction（H₂-TPR），and X-ray diffraction（XRD）. The results showed that the effect of calcination temperature on the catalyst was remarkable. The catalyst calcined at 500 ℃ had moderate BET surface area，pore volume and average pore diameter. As calcination temperature rose，the content of spinel copper increased，and the particle diameter of metal copper also increased. An appropriate calcination temperature could ensure a suitable strength of interaction between metal and carrier to achieve higher reactivity and stability. The optimum calcination temperature was 500 ℃.

An efficient process for preparation of 5-hydroxymethylfurfural（HMF）from glucose was developed with ionic liquid 1-butyl-3-methyl imidazolium chloride（[BMIM][Cl]）as solvent and CrCl₃ as catalyst. A HMF yield of above 70% could be obtained at 130 ℃ in 20 min. Recycle of the ionic liquid and CrCl₃ demonstrated constant activity after 5 cycles of use.

Highly stable Co²⁺-NaX catalyst was prepared from Co²⁺-NaX，which was prepared by five times of solid-state ion-exchange，calcination at 500 ℃ for 6 h and then another solid-state ion-exchange. ICP results showed that mass fraction of Co²⁺ in the highly stable Co²⁺-NaX catalyst was 9.13%，which exceeded equilibrium Co²⁺ mass fraction in Co²⁺-NaX prepared by five times of solid-state ion-exchange（8.42%）. The catalysts were characterized by XRD and N₂ adsorption- desorption. The results indicated that the framework of NaX was not destroyed after Co²⁺ exchange，whereas the ordering of NaX decreased with increasing content of Co²⁺ into the zeolite. The optimal conditions were obtained by orthogonal experiments as：styrene 6 mL，catalyst 1.0 g，solvent 48 mL，reaction temperature 80 ℃ and reaction time 6 h. Under such conditions，the average yield of styrene oxide was 39.5%. The catalyst prepared by this method showed higher catalytic activity than Co²⁺-NaX prepared only by five times of solid-state ion-exchange，and the activity was stable after reuse.

In order to expand the optical response of titania into the visible light region，carbon-doped titania powders were prepared by the hydrolysis method and other steps. The prepared samples were then characterized with XRD，XPS and UV-Vis diffuse reflectance spectroscopy. Moreover，the photocatalytic activities of the samples in the visible light region were tested，and the influences of different carbon resource on the photocatalytic activity were investigated. The doping of carbon led to an increase in optical absorption intensity in the visible light region，which result in high visible light photocatalytic activity with carbon doped titania in the decoloration of methyl orange.

Diamondoids are cage-like saturated hydrocarbons consisting of fused cyclohexane rings. This family of organic compounds follows the general chemical formula of C_4n+6 H_4n+12. Adamantane is the smallest member of the diamondoids family with n=1, whose C skeleton structure is similar to the diamond lattice. Due to the special cage structure and the superexcellent physical，chemical and pharmacological properties，diamondoids have been a hot topic of research. Structure，nomenclature，properties of diamondiods，especially chemical properties and synthesis of the derivatives of diamondoids are reviewed.

9,10-dihydro-9-oxa-10-phos-phaphenanthrene-10-oxide（DOPO）and its derivatives could be used to synthesize the phosphorus-containing epoxy resin and the curing agent，for preparing the reactive flame retardant epoxy resin. The DOPO-based epoxy resin is more durable and efficient and has become the main direction of development. The research progress is reviewed.

Polylactic acid（PLA）is widely used in agriculture，packaging，medicine and health care because it is a biocompatible，biodegradable and bioabsorbable polymer and has fine mechanical property. But it is hard and brittle and has poor pliability because it has a high glass transition temperature. Thus，it has to be modified to enhance its pliability to improve handling and application. In this paper，the recent research progress of toughening modification of PLA via copolymerization，cross-linking，and blending is reviewed.

A novel PVC-based form-stable phase change materials（FSPCM）plates，which comprised of micro-encapsulated PCM（MEPCM）as latent heat storage medium and polyvinyl chloride（PVC）as matrix，was prepared by blending and compression molding. Their microscopic pattern，thermo-physical properties，thermal stability and mechanical properties were characterized. The results showed that the phase change temperature was between 3 ℃ and 18 ℃. When the content of MEPCM was 10%，the prepared PVC-based FSPCM plates were the best，whose blending strength，blending modulus，tensile strength and impact strength were up to 26.7 MPa，3.48 GPa，9.8MPa and 10 kJ/m².

Monodisperse molecularly imprinted polymer microsphere（MIPMs）for chloramphenicol was prepared by two-step seed swelling using linear polystyrene emulsion as seeds，methacrylic acid（MAA）as functional monomer and ethylene glycol dimethacrylate（EDMA）as crosslinker. The influences of swelling ratio，stirring speed，ratio of water to oil，dosage of cross-linker and dispersant on the morphology，size and size distribution of the MIPMs were investigated by scanning electron microscopy（SEM）. Furthermore，static adsorption was used to evaluate the recognition properties of the MIPMs. When the swelling ratio was 40，stirring speed was 150 r/min around，ratio of water to oil was (8∶1)—(11∶1)，dosage of cross-linker was 20 mmol，dosage of dispersant was 1.2 g，a series of uniformly sized MIPMs with good dispersion were obtained. When 4 mmol MAA was used as the functional monomer，and the dosage of crosslinker was 20 mmol，the prepared MIPMs exhibited the best recognition performance，and the separation factor was up to 5.57 when thiamphenicol was chosen as the competitive molecules. Two-step seed swelling opened a simple and effective approach to preparing MIPMs in water.

Neodymium-doped yttrium aluminium garnet（Nd:YAG）powders were synthesized by co-precipitation with forward-titration and reverse-titration，respectively. The phase composition，morphology，particle size distribution of the powders were determined. The powder obtained by forward-titration was of major-phase YAG and a trace amount of YAM with a grain size about 24.7 nm，while the powder by reverse-titration was of pure-phase YAG with a grain size 26.6 nm. The average particle sizes of these powders were 1.26 mm and 1.86 mm respectively. The former was well dispersed with a narrow size distribution. Nd:YAG transparent ceramic was sintered at 1800 ℃ in vacuum. A few pores were observed in the forward-titration sample as compared with a few big holes and more pores at the grain boundaries of the reverse-titration sample. The transmission of the polished samples with thickness of 1mm were 72% and 42% at 1064 nm，65% and 35% at 400 nm respectively.

Nano/micron-sized ZnO spheres were fabricated by homogeneous co-precipitation at 75 ℃. The prepared spheres were characterized by X-ray diffraction（XRD）and scanning electron microscope（SEM）. The effect of reaction time and HWP（H₃PW₁₂O₄₀∶HPW）concentration was investigated. The result showed that the ZnO spheres after 3h reaction had uniform sizes and dispersed well when the concentration of Zinc acetate dihydrate，TEA and HPW were 0.025 mol/L，0.100 mol/L and 1.00×10^－3 mol/L respectively.

A high-throughput screening method based on membrane for selecting cholesterol oxidase mutants with improved thermal activity was proposed. This method takes advantage of the fact that the process of enzyme treatment and the reaction between enzyme and substrate was separated effectively，thus preventing the enzyme from reaction with substrate before heat treatment. High temperature treatment only involved the membrane not the agar plate，thereby the problem of softening or melting of the agar plate was resolved. This method is applicable to the screening of mutant colonies with high activity which produce obvious reddish brown transparent circle on the agar plate. The nitrocellulose filter membrane used for transfer printing is cheap and the major advantages of this method are reliability and simple，rapid screening.

β-Co(OH)₂ was synthesized with cobalt sulfate，sodium hydroxide as raw materials，ammonia as complexing agent，and ascorbic acid as protective agent. The effects of reaction temperature，concentration of NaOH，molar ratio of complexing agent to cobalt ion on the yield were investigated，and the reaction conditions were optimized by response surface methodology（RSM）with three factors and three levels. A correlation model for the optimized synthesis yield of β-Co(OH)₂ was presented. The optimal synthesis conditions of β-Co(OH)₂ with ascorbic acid were as follows：reaction temperature 79 ℃，concentration of NaOH 2.89mol/L，ratio of complexing agent to cobalt ion 2.19，and the optimized yield was 97.40%. The structure of the product was verified by XRD.

The release of intercellular protein from yeast cells was proposed for protein modification. Saccharomyces cerevisiae protein isolate modified to improve its foaming ability was tested. Dry-heating treatment，thermal alkaline denaturalization and enzymatic hydrolysis were used，and the best results were obtained by using thermal alkaline denaturalization method with Ca(OH)₂ concentration of 1.5%，which increased maximum foam volume to 1109.1 mL，and foam stability time to 10.1 h. According to the Box-Behnken center-united experimental design principles，the method of response surface analysis with 3 factors and 3 levels was adopted. The optimum modification conditions were determined by analyzing the three-dimensional surface plot and contour plot and by solving the regression model equation with Design Expert software，which showed that reaction temperature of 77.88 ℃，time of 2.39 h，and Ca(OH)₂ concentration of 1.34% were the best conditions. Under the optimal conditions，the forecasted maximum foam volume was 1135.1 mL，and verified value was 1127.3 mL by confirmative test. The relative error was 0.72%，indicating that the regression equation was valid and reliable.

Hexafluorobutadiene is an original，efficient and environmental friendly etch gas for dielectric etch processing，which has been paid much attention to in semiconductor devices，manufacturing. This paper elaborates on the evolution and future direction of hexafluorobutadiene synthesis. Until today，the key for synthesis of hexafluorobutadiene mainly revolves around the preparation of two kinds of important intermediates，1,2,3,4-tetrahalo-hexafluorobutane and trifluorovinylzinc，but these synthesis methods are unsatisfactory from the perspective of commercialization. Finally，advantages and disadvantages of various methods are evaluated，and the commercialization prospect of hexafluorobutadiene synthesis is also discussed.

Poly diglycol cyclohexane 1,2-dicarboxylate was prepared from hexahydrophthalic anhydride and diethylene glycol，catalyzed by titanium complex tetrabutyl titanate. The best reaction conditions of esterification were determined as follows：molar ratio of diethylene glycol to hexahydrophthalic anhydride 1.1∶1，amount of catalyst 0.8%（based on the mass of hexahydrophthalic anhydride），reaction temperature 220 ℃，reaction time 5 h，vacuum reaction time 2.5 h，vacuum reaction temperature 220 ℃ under vacuum（－0.095 MPa），and esterification yield could be up to 99.0%. Number-average molecular weight of the product poly diglycol cyclohexane 1,2-dicarboxylate was 14000，and weight-average molecular weight of the product was 15000. Molecular weight distribution of the product was narrow.

In a micro fixed-bed reactor，preparation of ethylene glycol by catalytic hydrogenation of methyl glycolate using composite copper-based catalyst Cu-Cr was studied. The effects of mole ratio of hydrogen to methyl glycolate，reaction temperature，pressure，space velocity on the hydrogenation reaction were investigated. The activity of the catalysts was evaluated by XRD. The results showed that under optimized conditions of reaction temperature 210 ℃，reaction pressure around 3.5 MPa，molar ratio of hydrogen to methyl glycolate close to 40︰1，space velocity about 0.4 h^－1，the conversion of methyl glycolate to ethylene glycol reached 95%，and the molar selectivity of ethylene glycol reached 90 %.

Reburning of flue gas is an effective method for NO_x emission control in furnace during combustion of coal. The conventional reburning fuel，i.e.，natural gas and coal，was discussed with respect to their bottlenecks of reburning. Then the merit of waste tire as an alternative reburning fuel was analyzed and the state-of-the-art waste tire reburning was reviewed. The results showed that 86% original NO_x was reduced when waste tire combined with lignite ash was used as reburning fuel. NO_x reduction efficiency was as high as 88% when waste tire mixed with Fe₂O₃ was used for reburning，which was much higher than that of coal and natural gas. Waste tire has important engineering application advantage when it is used as reburning fuel，which is helpful for both its utilization as a new energy source and the reduction of NO_x pollutant emission.

As a novel type of technology which integrates membrane separation technology with conventional phase contacting operation，membrane absorption will be widely used in global green-house effect mitigation and industrial，medical and astronautic application. Based on the recent progress of CO₂ separation from flue gas，the related principles，characteristic，process technology and material selection，mass transfer and its influence factors were studied and analyzed. The effects of module structure，gas and absorber flow mode in the process and membrane material on the separation performance were critical，the same as for other membrane contactors. Further，temperature control in operation could greatly help to enhance process mass transfer due to the characteristics of absorption.

The distributions of hydrocarbon and non-hydrocarbon compounds of the pyrolysis oil generated from an industrial test facility were analyzed. The results showed that aromatics content and olefins content in the pyrolysis oil were high，and saturated hydrocarbons content was low，and the pyrolysis oil had high sulfur content，high nitrogen content and high acid value. The sulfur content increased with increasing boiling point of the pyrolysis oil fraction. Sulfur compounds were mainly thiophenes. Mercaptan sulfur mainly existed in the fractions with boiling point lower than 300 ℃. Sulfide sulfur mainly existed in the fractions with boiling point lower than 150 ℃ and higher than 500 ℃. With increasing boiling point，the total nitrogen content increased. Basic nitrogen content and non-basic nitrogen content were 1/3 and 2/3，respectively. Acidic compounds in the pyrolysis oil were mainly concentrated in the fractions with boiling point 200—400 ℃.

The effect of a new type solvent on volatile organic compounds（toluene）absorption was studied by experiments. The aqueous solution of sodium benzoate，sodium citrate and sodium tartrate were used as research objects and organic acids and silicate as absorbent additives. The results of single factor experiments and orthogonal tests showed that the absorption rate of toluene could reach 88% under the optimum absorption conditions. And the optimum absorption conditions were as follows，pH 6.0，mass fraction of the absorbent（sodium benzoate）8.0% ，spray volume 30 L/h，inlet vapor flow rate 315 L/h and the absorbent inlet temperature 15 ℃.

In this paper，liquid phase adsorption for removing trace mercaptan from C₆ feedstock is presented. The experimental results showed that modified NaY had the best adsorption with the adsorption capacity up to 1.56%. Meanwhile，adsorption process was influenced by operating conditions. Increasing temperature was not favorable for adsorption capacity，and decreasing space velocity of feeding could improve adsorption capacity，but water in C₆ feedstock could significantly reduce the adsorption performance of adsorbent. The adsorbent could be regenerated by calcination.

A large amount of high chemical oxygen demand（COD）wastewater was generated in the synthesis of sulf amonomethoxine drugs. Based on a novel non-styrene adsorptive resin synthesized by the authors，the research on the treatment of pharmaceutical wastewater was performed by the process of CaO flocculation sedimentation and resin adsorption. The results showed that COD of the original wastewater could be decreased to 321 mg/L from 11000 mg/L by the novel process. 84.33% and 81.66% COD removal percentages could be achieved by CaO flocculation sedimentation and resin adsorption，and the total COD removal efficiency was over 97%. After 5 times of adsorption-desorption cycles，the resins still kept high adsorptive capabilities. This simple and economical technique for pharmaceutical wastewater treatment shows good prospects for practical application．

A strain named JQ-1，which was good at removing formaldehyde，was screened from the collected activated sludge. The strain was preliminary identified as Pseudomonas sp. according to its morphology. The strain JQ-1 was inoculated on the packing in the bio-trickling filter，and then  system for biological treatment of waste gas containing formaldehyde by using a bio-trickling filter was established. After the system was stably，the experiment of using a bio-trickling filter to treat waste gas containing formaldehyde at low concentrations was performed. The experimental results showed that the removal efficiency of formaldehyde was up to over 93% when inlet formaldehyde concentration was less than 33 mg/m³. If it was over 33 mg/m³，the removal efficiency decreased significantly. As the inlet gas flow was continuously increasing，the removal efficiency was gradually declined. The removal efficiency dropped from 92.5% to 73.4% accompanied with the inlet gas flow increasing from 0.06 m³/h to 0.18 m³/h. The spray liquid flow was also an important factor to affect the removal efficiency of formaldehyde. When the spray liquid flow reached 1.8 L/h，the removal efficiency was the best and up to 92.7%. Based on the experimental data，the related basic theory was discussed.

Aiming at the deviation of actual feedstock composition from the original design for PetroChina Dushanzi 1 million ton per year ethylene plant，a set of optimized operation parameters obtained after adjustment，was proposed to maximize economic gains and profits.