Multi-linear regression model for chlorine consumption by waters

Guocheng Zhu,Shanshan Zhang,Yongning Bian,Andrew S Hursthouse 대한환경공학회 2021 Environmental Engineering Research Vol.26 No.4

In drinking water treatment, disinfection is a key step to ensure the safety of water quality and people’s health but little is known of the relationship between chlorine consumption and water matrix properties from varied sources (BWM). In this study, we measured the fluorescence from fractions of NOM (FFN) for the relevant BWM. This included the evaluation of three components: the chlorine-dependence factor (CDF) (DOC and NH₃-N), the BWM (such as NO₃⁻, NO₂⁻ and turbidity), and FFN (I-V fluorescence fractions). Multi-linear regression model was used to fit the data. Results showed that when using the CDF, BWM and FNN, in the prediction of chlorine consumption showed the (R²) values were 0.72, 0.71 and 0.41, respectively. While the FNN did not fit the model well it did enhance the model using CDF by 11.26%. The FNN is not effective in enhancement of the BWM response to the model. Combination of the CDF, BWM and FNN or that of the CDF and BWM were both effective in prediction of chlorine consumption.

Biocatalytic Production of Glucosamine from N-Acetylglucosamine by Diacetylchitobiose Deacetylase

( Zhu Jiang ),( Xueqin Lv ),( Yanfeng Liu ),( Hyun-dong Shin ),( Jianghua Li ),( Guocheng Du ),( Long Liu ) 한국미생물생명공학회(구 한국산업미생물학회) 2018 Journal of microbiology and biotechnology Vol.28 No.11

Glucosamine (GlcN) is widely used in the nutraceutical and pharmaceutical industries. Currently, GlcN is mainly produced by traditional multistep chemical synthesis and acid hydrolysis, which can cause severe environmental pollution, require a long prodution period but a lower yield. The aim of this work was to develop a whole-cell biocatalytic process for the environment-friendly synthesis of glucosamine (GlcN) from N-acetylglucosamine (GlcNAc). We constructed a recombinant Escherichia coli and Bacillus subtilis strains as efficient whole-cell biocatalysts via expression of diacetylchitobiose deacetylase (Dac_ph) from Pyrococcus furiosus. Although both strains were biocatalytically active, the performance of B. subtilis was better. To enhance GlcN production, optimal reaction conditions were found: B. subtilis whole-cell biocatalyst 18.6 g/l, temperature 40°C, pH 7.5, GlcNAc concentration 50 g/l and reaction time 3 h. Under the above conditions, the maximal titer of GlcN was 35.3 g/l, the molar conversion ratio was 86.8% in 3-L bioreactor. This paper shows an efficient biotransformation process for the biotechnological production of GlcN in B. subtilis that is more environmentally friendly than the traditional multistep chemical synthesis approach. The biocatalytic process described here has the advantage of less environmental pollution and thus has great potential for largescale production of GlcN in an environment-friendly manner.

A review on metal organic frameworks (MOFs) modified membrane for remediation of water pollution

Qian Yuan,Guocheng Zhu 대한환경공학회 2021 Environmental Engineering Research Vol.26 No.3

Porous metal-organic frameworks (MOFs) have received wide attention on the potential application to separation of pollutants from contaminated water to produce clear water. Recently, the report on MOFs modified membrane in pollution separation is very interesting. The main focus is that adding MOFs onto the surface of the membrane can significantly improve its separation performance and anti-fouling ability. This review took the opportunity to give readers a preliminary and detailing understanding of the basic knowledge of the MOFs modified membrane used in remediation of water pollution.

Occurrence and control of N-nitrosodimethylamine in water engineering systems

Yongning Bian,Chuang Wang,Guocheng Zhu,Bozhi Ren,Peng Zhang,Andrew S. Hursthouse 대한환경공학회 2019 Environmental Engineering Research Vol.24 No.1

N-nitrosodimethylamine (NDMA) is a typical nitrogen disinfection by-product, which has posed a potential threat to human health during drinking water disinfection. Because of the well-known effects of mutagenesis, carcinogenesis and teratogenesis, the high detection rate in water engineering systems (such as coagulation, membrane filtration and biological systems), and difficulty to remove, it has received wide concern in the field of water engineering systems. The NDMA is a low molecular weight hydrophilic organic substance, which is difficult to remove. Also, the mechanism for NDMA formation is also recognized to be complex, and many steps still needed to be further evaluated. Therefore, the mechanistic knowledge on NDMA formation potential and their removal processes is of particularly interest. Few papers summarize the occurrence and control of NDMA in water engineering systems. It is for this reason that the content of this paper is particularly important for us to understand and control the amount of NDMA thus reducing the threat of disinfection by-products to drinking water. Four parts including the mechanisms for the NDMA formation potential, the factors affecting the NDMA formation potential, the technologies for removal of NDMA are summarized. Finally, some definite suggestions are given.

Enhanced Cutinase Production of Thermobifida fusca by a Two-stage Batch and Fed-batch Cultivation Strategy

Gangqiang He,Guanghua Huo,Liming Liu,Yang Zhu,Jian Chen,Guocheng Du 한국생물공학회 2009 Biotechnology and Bioprocess Engineering Vol.14 No.1

In this study, cutinase production by Thermobifida fusca WSH03-11 was investigated with mixed short-chain organic acids as co-carbon sources to demonstrate the possibility of producing high value-added products from organic wastes. T. fusca WSH03-11 was cultured with different combinations of butyrate, acetate, and lactate with a purpose of increasing cutinase activity. The optimum proportion of butyrate, acetate, and lactate was 4:1:3. In batch cultivation, acetate and lactate were consumed quickly, while the consumption of butyrate was depressed in the presence of acetate with a concentration higher than 0.5 g/L. Based on these results, a two-stage batch and fed-batch cultivation strategy was proposed: a batch culture with acetate and lactate as the co-carbon sources in the first 10 h, and then a fed-batch culture with a constant butyrate feeding rate of 12 mL/h during 11~20 h. By this two-stage cultivation strategy, cutinase activity, dry cell weight, and con-sumption rate of butyrate were increased by 70%, 103.4%, and 4.3-fold, respectively, compared to those of the batch cultivation. These results provided a novel and efficient way to produce high value-added products from organic wastes.

Metal Coating on Ultrafine Polyester Non-woven Fabrics and Their Ageing Properties

Azam Ali,Vijay Baheti,Jiri Militky,Zaman Khan,Guocheng Zhu 한국섬유공학회 2019 Fibers and polymers Vol.20 No.7

The presented research work proposed a simple technique to metalize the milife fabric (very fine thickness) withsilver coating. The polyester fabrics were firstly sensitized with copper, and then silver plating was performed on the surface. The presence of silver over the fabric was observed by scanning electron microscope and respective EDX spectra. Thechange in the electrical conductivity, electromagnetic shielding and joule heating properties were examined for differentelectroplating time. The electrically conductive fabrics showed low electrical resistance with high EMI shielding overfrequency range of 30 MHz to 1.5 GHz. To have an idea about the durability of electrical conductivity under stretch load, the75 cycles of stretch and release were carried out. Furthermore, the heating performance of silver plated fabric was studiedthrough measuring the change in temperature at the surface of the fabric while applying a voltage difference across the fabric. Lastly, the effect of ageing parameters like washing, oxidation and sulfidation were examined on the functional and comfortproperties (i.e. thermal conductivity and stiffness) of conductive fabric.

Multifunctional nanofiber membrane with anti-ultraviolet and thermal regulation fabricated by coaxial electrospinning

Shuoshuo Wang,Wubin Chen,Lina Wang,Juming Yao,Guocheng Zhu,Baochun Guo,Jiri Militky,Mohanapriya Venkataraman,MING ZHANG 한국공업화학회 2022 Journal of Industrial and Engineering Chemistry Vol.108 No.-

Ultraviolet radiation is extremely harmful to humans and often occurs in high-temperature weather. Thedevelopment of intelligent textiles based on UV protection and thermal regulation is paramount. In thisresearch, we use coaxial electrospinning technology to prepare anti-ultraviolet smart thermo-regulatingnanofiber membranes. The zinc oxide (ZnO) and octadecane were incorporated into nanofibers with thepolyacrylonitrile (PAN)/ZnO as sheath and the octadecane as core successfully. The composite nanofibershave excellent comprehensive properties, the highest melting enthalpy is 111.38 J/g, and the UPF value is86.21. This multifunctional nanofiber membrane has broad prospects in outdoor products, electroniccomponent protection, and military products.

Nanofibrous membranes with antibacterial and thermoregulatory functions fabricated by coaxial electrospinning

Zhuofan Qin,Shuoshuo Wang,Lina Wang,Juming Yao,Guocheng Zhu,Baochun Guo,Jiri Militky,Mohanapriya Venkataraman,MING ZHANG 한국공업화학회 2022 Journal of Industrial and Engineering Chemistry Vol.113 No.-

Bacteria, viruses, and temperatures change can affect the preservation of food and medicines, so it is necessaryto develop an intelligent textile for antibacterial and thermal regulation. In this paper, we usedcoaxial electrospinning technology to achieve antibacterial thermo-regulating intelligent textiles. Thepolyacrylonitrile (PAN)/curcumin is the sheath, and n-octadecane is the core. The composite fiber hasexcellent comprehensive properties. When the curcumin concentration is 10 wt%, the antibacterial effectis the best, and the bacteriostatic rate is 100%. When the core feed rate is 0.25 mL/h, the latent heat canreach 123.94 J/g. The multifunctional textiles have potential application value in the clothing fabrics,preservation and storage quality of functional foods, biomedical products, and other fields.

Response surface methodology approach to optimize coagulation-flocculation process using composite coagulants

Huaili Zheng,Tiroyaone Tshukudu,Xuebin Hua,Jun Yang,Mingzhuo Tan,Jiangya Ma,Yongjun Sun,Guocheng Zhu 한국화학공학회 2013 Korean Journal of Chemical Engineering Vol.30 No.3

Response surface method and experimental design were applied as alternatives to the conventional methods for optimization of the coagulation test. A central composite design was used to build models for predicting and optimizing the coagulation process. The model equations were derived using the least square method of the Minitab 16 software. In these equations, the removal efficiency of turbidity and COD were expressed as second-order functions of the coagulant dosage and coagulation pH. By applying RSM, the optimum condition using PFPD1 was coagulant dosage of 384 mg/L and coagulation pH of 7.75. The optimum condition using PFPD2 was coagulant dosage of 390 mg/L and coagulation pH of 7.48. Confirmation experiment demonstrated a good agreement between experimental values and model predicted. This demonstrates that RSM and CCD can be successfully applied for modeling and optimizing the coagulation process using PFPD1 and PFPD2.

Highly antibacterial electrospun double-layer mats for preventing secondary wound damage and promoting unidirectional water conduction in wound dressings

Runnan Xu,MING ZHANG,Juming Yao,YAN WANG,Yafeng Ge,Dana Kremenakova,Jiri Militky,Guocheng Zhu 한국공업화학회 2023 Journal of Industrial and Engineering Chemistry Vol.119 No.-

The efficient absorption of wound exudate and the prevention of soft tissue infection are major concernsin wound repair. Good antibacterial agents and unique wound dressing structures can effectively reducewound infection, thereby accelerating wound healing. In some double-layer asymmetric wound dressings,antimicrobial agents are incorporated in the hydrophilic layer, and only a small fraction of theantimicrobial agent penetrates the hydrophobic fibre layer towards the interior of the wound. Therefore, in this study, we chose curcumin (Cur.)/cellulose acetate (CA) as the hydrophobic inner layer. Not only does this effectively allow Cur. to make contact with the lining of the wound but it also preventsthe wound from sticking. However, the mechanical properties of a single CA/Cur. layer are not ideal. Using polyacrylonitrile as the outer hydrophilic substrate improves the fibre mat mechanical properties. In addition, to further improve the hydrophilicity, the water contact angle was reduced by introducing ahydrophilic group (2-hydroxypropyl-b-cyclodextrin, b-CD) and changing the fibre roughness (nano-TiO2). Thus, wound dressings with high biocompatibility, excellent antibacterial properties, and unidirectionalwater conduction were constructed for preventing secondary wound damage. In terms of performance, ittook 40 minutes for water to enter the hydrophilic fibre layer from the hydrophobic fibre layer (the watercontact angle decreased from 121.24 to 85.42), and it took 25 minutes for water to completely enter thefibre mats (the water contact angle decreased from 85.42-0), which is effective for draining wound exudate. In terms of antibacterial properties, the antibacterial rates of Cur. (8 wt%) against Escherichia coliand Staphylococcus aureus were 82.4% and 92.57%, respectively. The Cur./CA@PAN/b-CD/TiO2 bilayerasymmetric nanofibrous mats mimic the semipermeability of the extracellular matrix (ECM) and havehigh biocompatibility, which is effective for preventing secondary wound damage. It can be used as alow-cost, high-performance wound dressing with medical material potential.