Experimental study on toluene removal by a two-stage plasma-biofilter system

Volatile organic compounds(VOCs) are typical pollutants that affect air quality.Discharge plasma is thought to be a potential method that can remove VOCs from flue gas.In this experiment,pulsed corona discharge plasma combined with a biological tower was carried out to remove the benzene series,and toluene was selected as the typical VOC.The results indicated that the removal efficiency of toluene by pulsed corona plasma was slightly higher than that of direct current(DC) corona plasma,while its energy efficiency was much higher than DC corona plasma.Under the optimal experimental conditions of pulse voltage 8.5 kV,initial toluene concentration 1400 mg m^(-3),and toluene flow rate of 121h^(-1),the toluene removal efficiency reached 77.11% by the single method of pulsed corona discharge plasma,and the energy efficiency was up to 1.515 g/(kW·h) under the pulse voltage of 4.0 kV.The trickling biofilter was constructed by using the screened and domesticated Acinetobacter baumannii,and the highest toluene removal efficiency by the pulsed corona discharge plasma combined with the trickling biofilter rose up to 97.84%.Part of the toluene was degraded into CO_(2),H_(2)O,and some intermediate products such as o-diphenol under the influence of Acinetobacter baumannii.When the remaining waste gas passed through the discharge plasma reactor,the benzene ring structure could be directly destroyed by the collision between toluene and plasma.Meanwhile,O·,OH·,and some other oxidizing radicals generated by the discharge also join into the oxidative decomposition of toluene and its intermediate products,thereby further improving the removal efficiency of toluene.Therefore,the two-stage plasma-biofilter system not only showed a high toluene removal efficiency,but also had a good energy efficiency.The results of this study will provide theoretical support and technical reference for industrial VOC treatment.

Performance with Respect to Flue Gas Composition of a Combined Desulfurization/Denitration Process Using Powder-Particle Fluidized Bed

A new combined desulfurization/denitration (DeSOx/DeNOx,) process was tested in this study. The process uses the so-called powder-particle fluidized bed (PPFB) as the major reactor in which a coarse DeNOx catalyst, several hundred micrometers in size, is fluidized by flue gas as the fluidization medium particles, while a continuously supplied fine DeSOx sorbent, several to tens of micrometers in diameter, is entrained with the flue gas. Ammonia for NOx reduction is fed to the bottom of the bed, thus, SOX and NOX are simultaneously removed in the single reactor. By adopting a model gas, SO2-NO-H2O-N2-air, to simulate actual flue gas in a laboratory-scale PPFB, simultaneous SO2 and NO removals were explored with respect to various gas components of flue gas. It was found that the variations of SO2 removal with concentrations (fractions) of oxygen, water vapor, SO2 and NO in flue gas are little affected by the simultaneous NOx reduction. However, the dependencies of NO removal upon such gas components are closely related to the inter-actions between DeSOx sorbent and DeNOx catalyst.

An adaptive image sparse reconstruction method combined with nonlocal similarity and cosparsity for mixed Gaussian-Poisson noise removal

Compressed sensing(CS) has achieved great success in single noise removal. However, it cannot restore the images contaminated with mixed noise efficiently. This paper introduces nonlocal similarity and cosparsity inspired by compressed sensing to overcome the difficulties in mixed noise removal, in which nonlocal similarity explores the signal sparsity from similar patches, and cosparsity assumes that the signal is sparse after a possibly redundant transform. Meanwhile, an adaptive scheme is designed to keep the balance between mixed noise removal and detail preservation based on local variance. Finally, IRLSM and RACoSaMP are adopted to solve the objective function. Experimental results demonstrate that the proposed method is superior to conventional CS methods, like K-SVD and state-of-art method nonlocally centralized sparse representation(NCSR), in terms of both visual results and quantitative measures.

Effect of Removing Toxic Substances Combined with Activating Blood Circulation on Stabilizing the Atherosclerotic Plaque and Unstable Angina

The therapeutic effects of activating blood circulation to remove stasis of Chinese medicine （CM） in the prevention and treatment of atherosclerotic diseases such as coronary artery disease and angina are generally acknowledged. In recent years, to further improve the therapeutic effects of those Chinese herbs on such diseases, we have carried out a series of studies of CM medications with the function of clearing heat and removing toxic substances combined with activating blood circulation to remove stasis.

An innovative wood-chip-framework substrate used as slow-release carbon source to treat high-strength nitrogen wastewater

Removal of nitrogen in wastewater before discharge into receiving water courses is an important consideration in treatment systems.However,nitrogen removal efficiency is usually limited due to the low carbon/nitrogen（C/N） ratio.A common solution is to add external carbon sources,but amount of liquid is difficult to determine.Therefore,a combined wood-chip-framework substrate（with wood,slag and gravel） as a slow-release carbon source was constructed in baffled subsurface-flow constructed wetlands to overcome the problem.Results show that the removal rate of ammonia nitrogen（NH_4~＋-N）,total nitrogen（TN） and chemical oxygen demand（COD） could reach 37.5%-85%,57.4%-86%,32.4%-78%,respectively,indicating the combined substrate could diffuse sufficient oxygen for the nitrification process（slag and gravel zone） and provide carbon source for denitrification process（wood-chip zone）.The nitrification and denitrification were determined according to the location of slag/gravel and wood-chip,respectively.Nitrogen removal was efficient at the steady phase before a shock loading using slag-wood-gravel combined substrate because of nitrification-denitrification process,while nitrogen removal was efficient under a shock loading with wood-slag-gravel combined substrate because of ANAMMOX process.This study provides a new idea for wetland treatment of high-strength nitrogen wastewater.