Wen Y. Liu

Bio: Wen Y. Liu is an academic researcher. The author has contributed to research in topics: Adsorption & Metagenomics. The author has an hindex of 1, co-authored 1 publications receiving 59 citations.

Continuous treatment of textile water by ozonation and coagulation

Abstract: A continuous process of combined ozonation and chemical coagulation was employed for treatment of textile wastewaters from several dyeing and finishing plants. Ozonation was found to be highly effective in color removal with complete discolorization of textile wastewater being achieved in less than 10 min in the continuous reactor. Chemical coagulation was observed to be mainly responsible for removing dissolved and suspended solids with a COD removal efficiency of up to 66%. The treatment efficiency of the combined process can be further enhanced when used in conjunction with the activated sludge process. Preliminary economic analysis of the process shows that ozonation for decolorization is highly competitive in terms of its total cost compared with use of decoloring agent. The cost saving is further complemented by a considerable improvement in the overall quality of the treated wastewater.

Effect and Mechanism of Titanium Nanomaterials on Microbial Community Structure and Function in Sequencing Batch Reactor

Abstract: A series doses (0–1.0 g/L) of titanium dioxide (TiO2) and titanate nanotubes (TNTs) were added into the sequencing batch reactor (SBR) to investigate the biological effect of titanium nanomaterials. TNTs and TiO2 showed a moderate suppressing effect on SBR performance, while TiO2 seemed to be more toxic. Further, 0.04 g/L TiO2 resulted in significant inhibition on the removal of methylene blue (p < 0.05, n = 30). Illumina high-throughput sequencing revealed that the two titanium nanomaterials changed the composition of the microbial community in SBR, and LEfSe (linear discriminant analysis effect size) and Random forests analyses identified genus Hylemonella as the biomarker with the highest contribution to community response. Metagenomic analysis indicated that the presence of nanomaterials downregulated the community metabolic pathways related to metabolism and led to degradation of xenobiotics and pollutants, agreeing with the decrease of treatment performance of SBR. The exposure test with pure Escherichia coli and isolated Pseudomonas taiwanensis demonstrated the nanotoxic mechanisms of TiO2 and TNTs in interaction with the microbial cell surface and elevation of the cellular reactive oxygen species (ROS) level. These nanotoxic effects could also be due to the enhanced community functions, such as membrane-associated proteins, respiratory chain complexes I/III, NADPH oxidase complexes, and the pathway of endocytosis.

Tri-functional lanthanum-based biochar for efficient phosphorus recovery, bacterial inhibition, and soil fertility enhancement

Abstract: Abstract Excess phosphorus (P) in water can lead to eutrophication and upset ecological balance. In this study, biochar with ultrathin two-dimensional nanosheets from the natural mesocarp of shaddock was chosen as the carrier. The highly dispersed and small particle size of La(OH) 3 on the surface of the nanosheets (MSBL3) was successfully achieved using chemical impregnation for the adsorption of P in aqueous solution, and the maximum adsorption capacity was 260.0 mg P g −1 [La]. The differences in surface crystallization of La(OH) 3 on biochar at different La loadings were analyzed using the high-precision characterization methods. After six adsorption–desorption cycles, MSBL3 retained 76.7% of its initial performance in terms of the P adsorption capacity. The preparation of 1 g of MSBL3 costs about RMB 1, and it could reduce the P concentration in 2.6 ton of Laoyu River water to below the eutrophication threshold; and the inhibitory effect of MSBL3 on the eutrophication of water bodies was confirmed by the growth state of water hyacinth. Furthermore, 0.1 M MSBL3 could inhibit Escherichia coli and Staphylococcus aureus up to 98.7% and 85.0%, respectively, which indicates that MSBL3 can be used to recover P from water and also to improve water quality. In addition, the growth of the maize seedlings verified that the P-absorbed MSBL3 waste is a good soil fertilizer and can solve the problem of post-treatment of the adsorbent. In conclusion, MSBL3 prepared in this study is a promising P sorbent for application. Graphical Abstract

TiO2-assisted photocatalytic degradation of azo dyes in aqueous solution: kinetic and mechanistic investigations A review

Abstract: The photocatalytic degradation of azo dyes containing different functionalities has been reviewed using TiO2 as photocatalyst in aqueous solution under solar and UV irradiation. The mechanism of the photodegradation depends on the radiation used. Charge injection mechanism takes place under visible radiation whereas charge separation occurred under UV light radiation. The process is monitored by following either the decolorization rate and the formation of its end-products. Kinetic analyses indicate that the photodegradation rates of azo dyes can usually be approximated as pseudo-first-order kinetics for both degradation mechanisms, according to the Langmuir–Hinshelwood model. The degradation of dyes depend on several parameters such as pH, catalyst concentration, substrate concentration and the presence of electron acceptors such as hydrogen peroxide and ammonium persulphate besides molecular oxygen. The presence of other substances such as inorganic ions, humic acids and solvents commonly found in textile effluents is also discussed. The photocatalyzed degradation of pesticides does not occur instantaneously to form carbon dioxide, but through the formation of long-lived intermediate species. Thus, the study focuses also on the determination of the nature of the principal organic intermediates and the evolution of the mineralization as well as on the degradation pathways followed during the process. Major identified intermediates are hydroxylated derivatives, aromatic amines, naphthoquinone, phenolic compounds and several organic acids. By-products evaluation and toxicity measurements are the key-actions in order to assess the overall process.

Decolourization of industrial effluents - available methods and emerging technologies - a review

Abstract: Water pollution control is presently one of the major thrust areas of scientific research. While coloured organic compounds generally impart only a minor fraction of the organic load to wastewaters, their colour renders them aesthetically unacceptable. Stringent regulating measures are coaxing industries to treat their waste effluents to increasingly high standards. Colour removal, in particular, has recently become an area of major scientific interest as indicated by the multitude of related research reports. During the past two decades, several decolourization techniques have been reported, few of which have been accepted by some industries. There is a need to find alternative treatments that are effective in removing dyes and colourants from large volume of effluents, which are cost-effective, like the biological or integrated systems. This article reviews some of the widely used and most promising industrial wastewater decolourization methods. Data on decolourizing efficiencies of different causative agents, obtained by means of different physical, chemical and biological methods are discussed. Further a critical review is made on the various treatment methodologies and emerging technologies with a note on their advantages and disadvantages.