Biocompatibile nanofiber based membranes for high-efficiency filtration of nano-aerosols with low air resistance.

Particulate matter (PMs) from combustion emissions (traffic, power plant, and industries) and the novel coronavirus (COVID-19) pandemic have recently enhanced the development of personal protective equipment against airborne pathogens to protect humans' respiratory system. However, most commercial face masks still cannot simultaneously achieve breathability and high filtration of PMs, bacteria, and viruses. This study used the electrospinning method with polyimide (PI) and polyethersulfone (PES) solutions to form a nanofiber membrane with low-pressure loss and high biocompatibility for high-efficiency bacteria, viruses, and nano-aerosol removal. Conclusively, the optimized nano-sized PI/PES membrane (0.1625 m2/g basis weight) exhibited conspicuous performance for the highest filtration efficiency towards PM from 50 to 500 nm (99.74 %), good filter quality of nano-aerosol (3.27 Pa-1), exceptional interception ratio against 100-nm airborne COVID-19 (over 99 %), and non-toxic effect on the human body (107 % cell viability). The PI/PES nanofiber membrane required potential advantage to form a medical face mask because of its averaged 97 % BEF on Staphylococcus aureus filiation and ultra-low pressure loss of 0.98 Pa by referring ASTM F2101-01. The non-toxic PI/PES filters provide a new perspective on designing excellent performance for nano-aerosols from air pollution and airborne COVID-19 with easy and comfortable breathing under ultra-low air flow resistance.

Enhancement of Electrical Properties by a Composite FePc/CNT/C Cathode in a Bio-Electro-Fenton Microbial Fuel Cell System.

This study focused on an iron phthalocyanine compound with aligned CNTs on the surface of a carbon felt electrode (FePc/CNT/C) to enhance the bio-electro-Fenton microbial fuel cell system cathodes reaction rate of hydrogen peroxide and the electrical plate. Experiments of polarization curves and power density, decolorization of Reactive Black 5 (RB5), and scanning electron microscopy (SEM) measured the characteristics of the cathode plate. FePc/CNT/C presented better electrical properties (open-circuit voltage, maximum current density, and maximum power density) than that of CNT/C and C, as FePc is a catalyst and its planar structure could easily adhere to CNT to enhance the reduction reaction at the cathode and provide higher specific surface area. The optimal decolorization of RB5 dye, as achieved with the FePc/CNT/C electrode, was 61.79% among the three cathode electrodes in the bio-electro-Fenton microbial fuel cell system, and the maximum number of hydroxyl radicals was generated for the cathode electrode of FePc/CNT/C. These results suggest that the bio-electro-Fenton microbial fuel cell system could be applied as an energy-saving and efficient approach for dye-containing wastewater treatment.

Adsorption Behavior of Recyclable Magnetites with N-Components for Adsorption of Copper Ion.

Recyclable magnetites with thioureido group (poly-allyl-thiourea/oleic acid/magnetite, PAT-adsorbent) and amine functional group (ethylenediamine/methyl methacrylate/oleic acid/magnetite, EDA-adsorbent) were synthesized by modifying magnetite with oleic acid, methyl methacrylate, allyl thiourea and ethylenediamine. PAT-adsorbent and EDA-adsorbent were used and compared for adsorption of copper ions in a batch system due to the existence of amino group (-NH2) both on thioureido group and amine functional group. The kinetics of both PAT-adsorbent and EDA-adsorbent were evaluated utilizing pseudo-first-order and pseudo-second-order kinetic models. The equilibrium data was analyzed and compared using the Langmuir and Freundlich isotherm models. The maximum adsorption capacity (Qm) of PAT-adsorbent (19.126 mg g-1) was higher than that of EDA-adsorbent (7.096 mg g-1). As compared to EDA-adsorbent the magnetic adsorbent (PAT-adsorbent) with good desorption performance (>85% desorption efficiency) and easily reuse (>85% recovery by magnetic force) was the important factors for its potential practical application.

Reclamation of zinc-contaminated soil using a dissolved organic carbon solution prepared using liquid fertilizer from food-waste composting.

A liquid fertilizer obtained through food-waste composting can be used for the preparation of a dissolved organic carbon (DOC) solution. In this study, we used the DOC solutions for the remediation of a Zn-contaminated soil (with Zn concentrations up to 992 and 757 mg kg(-1) in topsoil and subsoil, respectively). We then determined the factors that affect Zn removal, such as pH, initial concentration of DOC solution, and washing frequency. Measurements using a Fourier Transform infrared spectrometer (FT-IR) revealed that carboxyl and amide were the major functional groups in the DOC solution obtained from the liquid fertilizer. Two soil washes using 1,500 mg L(-1) DOC solution with a of pH 2.0 at 25°C removed about 43% and 21% of the initial Zn from the topsoil and subsoil, respectively. Following this treatment, the pH of the soil declined from 5.4 to 4.1; organic matter content slightly increased from 6.2 to 6.5%; available ammonium (NH4(+)-N) content increased to 2.4 times the original level; and in the topsoil, the available phosphorus content and the exchangeable potassium content increased by 1.65 and 2.53 times their initial levels, respectively.

Preparation and Application of Modified Magnetic Particles to Remove Phosphate in Aqueous Media.

In this work, magnetic particles were firstly protected by oleic acid, and then polymers, the polymers was prepared with allyl-thiourea as the functional monomer, ethyleneglycol dimethacrylate as the cross-linking agent, 2,2-azobisisobutyronitrile as the initiator, and acetonitrile as the solvent. The magnetic polymers were analyzed by FT-IR, X-ray diffraction, and a vibrating sample magnetometer to obtain the morphological and magnetic properties. The adsorption of phosphate on the magnetic polymers was investigated, including pH effect, initial concentration, and temperature. The results proved that the adsorbent was paramagnetic and successfully loaded with the poly-thiourea group. The data was well fitted to the Langmuir adsorption isotherm, and the maximum adsorption capacity was 55.20 mg-P g(-1). Furthermore, desorption of phosphate from the adsorbent could be achieved efficiently by 0.5 mol L(-1) NaOH, reusability was studied by repeating adsorption-desorption cycles five times.

Adsorption of Phosphate in Aqueous Solution by Magnetite Modified with Diethylenetriamine.

A magnetic adsorbent, amine-functionalized silica magnetite (NH2-Al/SiO2/Fe3O4), has been synthesized to behave as an cationic adsorbent by adjusting the pH value of the aqueous solution to make amino groups protonated. NH2-Al/SiO2/Fe3O4 was used to adsorb phosphate ions in an aqueous solution in a batch system, and the maximum adsorption were found to occur at pH 3.0. The adsorption equilibrium data were all fitted the Langmuir isotherm equation reasonably well, and the maximum adsorption capacities of phosphate ions were more than 40 mg g(-1) and increased with elevating temperature. The enthalpy (ΔH0) and entropy (ΔS0) values of NH2-Al/SiO2/Fe3O4 with the adsorption reaction of phosphate ions were 11.98 KJ mol(-1) and 0.095 KJ (T mol)(-1), respectively. A pseudo-second-order model also could best describe the adsorption kinetics, and the derived activation energy for phosphate ions was 20.2 kJ mol(-1). The optimum condition to desorb phosphate ions from NH2-Al/SiO2/Fe3O4 is provided by a solution with 0.05 M NaOH.

Adsorption Removal of Environmental Hormones of Dimethyl Phthalate Using Novel Magnetic Adsorbent.

Magnetic polyvinyl alcohol adsorbent M-PVAL was employed to remove and concentrate dimethyl phthalate DMP. The M-PVAL was prepared after sequential syntheses of magnetic Fe3O4 (M) and polyvinyl acetate (M-PVAC). The saturated magnetizations of M, M-PVAC, and M-PVAL are 57.2, 26.0, and 43.2 emu g(-1) with superparamagnetism, respectively. The average size of M-PVAL by number is 0.75 µm in micro size. Adsorption experiments include three cases: (1) adjustment of initial pH (pH0) of solution to 5, (2) no adjustment of pH0 with value in 6.04-6.64, and (3) adjusted pH0 = 7. The corresponding saturated amounts of adsorption of unimolecular layer of Langmuir isotherm are 4.01, 5.21, and 4.22 mg g(-1), respectively. Values of heterogeneity factor of Freundlich isotherm are 2.59, 2.19, and 2.59 which are greater than 1, revealing the favorable adsorption of DMP/M-PVAL system. Values of adsorption activation energy per mole of Dubinin-Radushkevich isotherm are, respectively, of low values of 7.04, 6.48, and 7.19 kJ mol(-1), indicating the natural occurring of the adsorption process studied. The tiny size of adsorbent makes the adsorption take place easily while its superparamagnetism is beneficial for the separation and recovery of micro adsorbent from liquid by applying magnetic field after completion of adsorption.

Photocatalytic characteristic and photodegradation kinetics of toluene using N-doped TiO2 modified by radio frequency plasma.

This study investigates the feasibility of applications of the plasma surface modification of photocatalysts and the removal of toluene from indoor environments. N-doped TiO2 is prepared by precipitation methods and calcined using a muffle furnace (MF) and modified by radio frequency plasma (RF) at different temperatures with light sources from a visible light lamp (VLL), a white light-emitting diode (WLED) and an ultraviolet light-emitting diode (UVLED). The operation parameters and influential factors are addressed and prepared for characteristic analysis and photo-decomposition examination. Furthermore, related kinetic models are established and used to simulate the experimental data. The characteristic analysis results show that the RF plasma-calcination method enhanced the Brunauer Emmett Teller surface area of the modified photocatalysts effectively. For the elemental analysis, the mass percentages of N for the RF-modified photocatalyst are larger than those of MF by six times. The aerodynamic diameters of the RF-modifiedphotocatalyst are all smaller than those of MF. Photocatalytic decompositions of toluene are elucidated according to the Langmuir-Hinshelwood model. Decomposition efficiencies (eta) of toluene for RF-calcined methods are all higher than those of commercial TiO2 (P25). Reaction kinetics ofphoto-decomposition reactions using RF-calcined methods with WLED are proposed. A comparison of the simulation results with experimental data is also made and indicates good agreement. All the results provide useful information and design specifications. Thus, this study shows the feasibility and potential use of plasma modification via LED in photocatalysis.

Influence of calcination temperature on structure, magnetic property, photocatalytic activity and recovery of recyclable photocatalysts.

The photocatalytic oxidation of titanium dioxide is conducted in a suspension of submicrometer-sized particles, and an additional separation step is required to recover these catalyst particles from treated water, which presents a major drawback in treating wastewater. In this study, magnetic photocatalysts of spinel structure Fe3O4 coated with SiO2 and TiO2 by employing various heat treatments were synthesized and their characterization was carried out by thermogravimetric analysis, X-ray diffraction, vibrating sample magnetometry, and Fourier transform infrared spectroscopy. Furthermore, the reaction behavior in photocatalytic processes involving photocatalysts of porous composite for treating wastewater were analyzed to enhance their activity and recovery. The results showed that the calcination temperatures of the magnetic photocatalysts significantly affect their properties, i.e., rutile ratio, magnetization, surface area, and photocatalytic activity. The photocatalytic activity of these catalysts was measured using the decomposition of benzoic acid, which can be well modeled by the Langmuir-Hinshelwood kinetic equation. Furthermore, because of the paramagnetic behaviors of the prepared TiO2/SiO2/Fe3O4, these magnetic photocatalyst could be easily recovered by applying a magnetic field.

Optimizing treatment of benzoic acid by ozone process with recyclable catalyst of magnetism.

This study is to optimize the multi-quality performance of magnetic catalyst/ozone process by combining a technique for order performance by similarity to ideal solution (TOPSIS) with the Taguchi method, which simultaneously has the best decomposition rate constant of benzoic acid and removal rate constant of total organic carbon (TOC). The optimal experimental parameters were pH of 7, initial concentration of 75 ppm and catalyst loading of 0.05 g/L. More than 93% of the magnetic catalyst was easily separated and redispersed for reuse by the magnetic force due to the paramagnetic behaviours of the prepared SiO2/Fe3O4. It is believed that through the joint efforts improvement, design and manufacturing, new separation and recycling technologies will be available and more easily recyclable magnetic catalysts will be developed in the future.

Application of bifunctional magnetic adsorbent to adsorb metal cations and anionic dyes in aqueous solution.

A magnetic adsorbent, amine-functionalized silica magnetite (NH(2)/SiO(2)/Fe(3)O(4)), has been synthesized to behave as an anionic or cationic adsorbent by adjusting the pH value of the aqueous solution to make amino groups protonic or neutral. NH(2)/SiO(2)/Fe(3)O(4) were used to adsorb copper ions (metal cation) and Reactive Black 5 (RB5, anionic dye) in an aqueous solution in a batch system, and the maximum adsorption were found to occur at pH 5.5 and 3.0, respectively. The adsorption equilibrium data were all fitted the Langmuir isotherm equation reasonably well, with a maximum adsorption capacity of 10.41 mg g(-1) for copper ions and of 217 m g g(-1) for RB5. A pseudo-second-order model also could best describe the adsorption kinetics, and the derived activation energy for copper ions and RB5 were 26.92 kJ mol(-1) and 12.06 kJ mol(-1), respectively. The optimum conditions to desorb cationic and anionic adsorbates from NH(2)/SiO(2)/Fe(3)O(4) were provided by a solution with 0.1M HNO(3) for copper ions and with 0.05 M NaOH for RB5.

Assessment upon azo dye decolorization and bioelectricity generation by Proteus hauseri.

This study explored dye decolorization and bioelectricity generation of indigenous Proteus hauseri ZMd44 for dye-bearing wastewater treatment. Chemical structures of azo dyes apparently affected the performance of dye biodecolorization. Additions of diazo dye C.I. reactive blue 160 (RBu160) stimulated simultaneous dye decolorization and bioelectricity generation of ZMd44 in single chamber microbial fuel cells (MFCs). However, high-level additions of RBu160 repressed capabilities of power production in MFC due to competition of electrons used for reductive decolorization. Decolorized intermediates of RBu160-phenyl methadiamine and 5-sulfoanthranilic acid as electron shuttles might mediate electron transport for current generation in MFC.

Waste brick's potential for use as a pozzolan in blended Portland cement.

This study investigated the pozzolanic reactions and engineering properties of waste brick-blended cements in relation to various replacement ratios (0-50%). The waste brick consisted of SiO(2) (63.21%), Al(2)O(3) (16.41%), Fe(2)O(3) (6.05%), Na(2)O (1.19%), K(2)O (2.83%) and MgO (1.11%), and had a pozzolanic activity index of 107%. The toxic characteristic leaching procedure (TCLP) results demonstrate that the heavy-metal content in waste bricks met the Environmental Protection Agency regulatory limits. Experimental results indicate that 10, 20, 30, 40 and 50% of cement can be replaced by waste brick, which causes the initial and final setting times to increase. Compressive strength development was slower in waste brick-blended cement (WBBC) pastes in the early ages; however, strength at the later ages increased significantly. Species analyses demonstrate that the hydrates in WBBC pastes primarily consisted of Ca(OH)(2) and calcium silicate hydrate (C-S-H) gel, like those found in ordinary Portland cement (OPC) paste. Pozzolanic reaction products formed in the WBBC pastes, in particular, various reaction products, including hydrates of calcium silicates (CSH), aluminates (CAH) and aluminosilicates (CASH), formed as expected, resulting in consumption of Ca(OH)(2) during the late ages of curing. The changes in the properties of WBBC pastes were significant as blend ratio increased, due to the pores of C-S-H gels and CAH filling via pozzolanic reactions. This filling of gel pores resulted in densification and subsequently enhanced the gel/space ratio and degree of hydration. Experimental results demonstrate waste brick can be supplementary cementitious material.

Mineralization of reactive Black 5 in aqueous solution by ozone/H2O2 in the presence of a magnetic catalyst.

Particles are often too small to be separated from a reaction system and recycled, especially in wastewater treatment via a catalytic ozonation process. Thus, the objective of this study was to prepare a magnetic catalyst (SiO(2)/Fe(3)O(4)) that can be recycled by using an external magnetic field. The effects of the characteristics of the magnetic catalyst, pH values, catalyst dosage, and initial concentration of Reactive Black 5 (RB5) on mineralization efficiency of the magnetic catalyst/H(2)O(2)/O(3) process were also investigated. The mineralization efficiency of RB5 under various conditions followed the sequence: SiO(2)/Fe(3)O(4)/H(2)O(2)/O(3)>SiO(2)/Fe(3)O(4)/O(3)>Fe(3)O(4)/O(3) approximately H(2)O(2)/O(3)>O(3)>SiO(2)/Fe(3)O(4)/H(2)O(2). Given the results of our reuse and recovery experiments, the magnetic catalyst shows considerable promise for use in water treatment.

Biosorption of chromium, copper and zinc by wine-processing waste sludge: single and multi-component system study.

Wine-processing waste sludge (WPWS) has been shown to have powerful potential for sorption of some heavy metals (i.e., chromium, lead and nickel) in single-component aqueous solutions. But although most industrial wastewater contains two or more toxic metals, there are few sorption studies on multicomponent metals by WPWS. This study has two goals: (i) conduct competitive adsorption using Cr, Cu and Zn as sorbates and examine their interaction in binary or ternary systems; and (ii) determine the effects of temperature on the kinetic sorption reaction. The sludge tested contained a high amount of organic matter (38%) and had a high cation exchange capacity (CEC, 255 cmol(c)kg(-1)). Infrared analysis reveals that carboxyl is the main functional group in this WPWS. The (13)C NMR determination indicates alkyl-C and carboxyl-C are major organic functional groups. At steady state, there are about 40.4% (Cr), 35.0% (Cu) and 21.9% (Zn) sorbed in the initial 6.12 mM of single-component solutions. Only pseudo-second-order sorption kinetic model successfully describes the kinetics of sorption for all experimental metals. The rate constants, k(2), of Cr, Cu and Zn in single-component solutions are 0.016, 0.030 and 0.154 g mg(-1)min(-1), respectively. The sorption of metals by WPWS in this competitive system shows the trend: Cr>Cu>Zn. Ions of charge, hydrated radius and electronic configuration are main factors affecting sorption capacity. The least sorption for Zn in this competitive system can be attributed to its full orbital and largest hydrated radius. Though the effect of temperature on Zn sorption is insignificant, high temperature favors the other metallic sorptions, in particular for Cr. However, the Cr sorption is lower than Cu at 10 degrees C. The Cr sorption by WPWS can be higher than that of Cu at 30 degrees and 50 degrees C.

Study on the indoor volatile organic compound treatment and performance assessment with TiO2/MCM-41 and TiO2/quartz photoreactor under ultraviolet irradiation.

Volatile organic compounds (VOCs) are the cause of indoor air pollution and are readily emitted from furniture and cleaning agents. In Taiwan, the concentrations of indoor VOCs range roughly from 1 to 10 ppm. It is important to effectively reduce indoor VOC emissions and establish the implementation of long-term, low-cost, controlled techniques such as those found in the ultraviolet/titanium dioxide (UV/TiO2) control systems. This study evaluates the performance of a photoreactor activated by visible irradiation and packed with TiO2/quartz or TiO2/mobile catalytic material number 41 (MCM-41). The photocatalysts tested include commercial TiO2 (Degussa P-25) and synthesized TiO2 with a modified sol-gel process. The UV light had a wavelength of 365 nm and contained an 8-W, low-pressure mercury lamp. Reactants and products were analyzed quantitatively by using gas chromatography with a flame-ionization detector. It is important to understand the influence of such operational parameters, such as concentration of pollutant, temperature, and retention time of processing. The indoor concentrations of VOCs varied from 2 to 10 ppm. Additionally, the temperatures ranged from 15 to 35 degrees C and the retention time tested from 2 to 8.2 sec. The results show that quartz with TiO2 had a better photoreductive efficiency than quartz with MCM-41. The toluene degradation efficiency of 77.4% with UV/TiO2/quartz was larger than that of 54.4% with the UV/TiO2/MCM-41 system under 10-min reaction time. The degradation efficiency of the UV/TiO2 system decreased with the increasing concentrations of indoor VOCs. The toluene degradation efficiency at 2 ppm was approximately 5 times greater than that at 10 ppm. The photoreduction rate of the VOCs was also evaluated with the Langmuir-Hinshewood model and was shown to be pseudo-first-order kinetics.

Photodegradation kinetics of formaldehyde using light sources of UVA, UVC and UVLED in the presence of composed silver titanium oxide photocatalyst.

This study investigated the surface modification of photocatalyst and photodecomposition of formaldehyde from indoor pollution source. This study explored the feasibility of the application of the ultraviolet light emitting diode (UVLED) instead of the traditional ultraviolet (UV) lamp to treat the formaldehyde. The photocatalytic decomposition of formaldehyde at various initial concentrations was elucidated according to the Langmuir-Hinshelwood model. The reaction rate constant (k) and adsorption equilibrium constant (K(L)) over 0.334 g silver titanium oxide photocatalyst (Ag/TiO2) coated on glass sticks with 254 nm ultraviolet lamp (UVC), 365 nm ultraviolet lamp (UVA), and UVLED are 650 ppmv min(-1) and 2 x 10(-4)ppmv(-1), 500 ppmv min(-1) and 1.04 x 10(-4)ppmv(-1), and 600 ppmv min(-1) and 2.52 x 10(-5)ppmv(-1), respectively. A comparison of the simulation results with the experimental data was also made, indicating good agreement. The magnitudes of energy effectiveness (E(e)) are in the order of UVLED (0.6942 mg kW(-1)h(-1))>UVA (0.007 mg kW(-1)h(-1))>UVC (0.0053 mg kW(-1)h(-1)). The E(e) of UVLED is 131 times larger than that of UVC. The UVLED can save a lot of energy in comparison with the traditional UV lamps. Thus, this study showed the feasible and potential use of UVLED in photocatalysis.

Degradation of di-n-butyl phthalate using photoreactor packed with TiO2 immobilized on glass beads.

This study evaluated the performance of a photoreactor packed with TiO2/glass, TiO2 immobilized on glass beads, initiated by UV irradiation, denoted as UV/TiO2/glass, to decompose di-n-butyl phthalate (DBP) in an aqueous solution. The photodegradation rate of DBP by this UV/TiO2/glass process was found to obey pseudo first-order kinetics represented by the Langmuir-Hinshelwood model. The experimental results of this study show that the influence of pH value of an aqueous solution to reaction rate was negligible at the pH values 4.5-9. The effect of cations on the photodegradation rate of DBP reveals that the larger the charge and size of cations contained, the more the inhibition of reaction rate increased. The UV/TiO2/glass process yielded a 75% degradation efficiency of DBP with initial concentration of 5 mg L(-1) at 80 min reaction time.

Kinetic studies of adsorption of lead(ll) from aqueous solution by wine-processing waste sludge.

A waste sludge produced from a wine-processing wastewater treatment process was used as an adsorbent to removal of heavy metal-lead(II) from aqueous solution. Results of kinetic experiments demonstrated that the adsorption was effective and rapid. Four different kinds of adsorption kinetic models (i.e., pseudo-first-order, pseudo-second-order, and two intra-particular mass diffusion models) were used to investigate the adsorption mechanisms. A normalized standard deviation was used to find the best adsorption kinetic model for the removal of lead(ll) by the sludge. The comparison shows that the kinetic adsorption data can be well-described by the pseudo-second-order adsorption model and that sorption might be a rate-limiting control. The adsorption-rate constant and adsorption capacity of pseudo-second-order adsorption equation were calculated. The parameters (initial lead(II) concentration, sludge-particle size, and sludge dosages), which affect the adsorption capacity of sludge, were discussed by using the pseudo-second-order adsorption equation.

Photochemical mineralization of di-n-butyl phthalate with H2O2/Fe3+.

This study evaluated the performance of photo-Fenton reaction initiated by the UV irradiation with H(2)O(2)/Fe(3+), denoted as UV/H(2)O(2)/Fe(3+), to decompose di-n-butyl phthalate (DBP) in the aqueous solution. The concentration of total organic carbon (TOC) was chosen as a mineralization index of the decomposition of DBP by the UV/H(2)O(2)/Fe(3+) process. A second-order kinetic model with respect to TOC was adequately adopted to represent the mineralization of DBP by the UV/H(2)O(2)/Fe(3+) process. The experimental results of this study suggested that the dosages with 4.74 x 10(-5) mol min(-1)L(-1) H(2)O(2) and initial Fe(3+) loading concentration of 4.50 x 10(-4) mol L(-1) in the solution at pH 3.0 with 120 microW cm(-2) UV (312 nm) provided the optimal operation conditions for the mineralization of DBP (5 mg L(-1)) yielding a 92.4% mineralization efficiency at 90 min reaction time.