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Membrane distillation (MD) has been increasingly explored for treatment of various hyper saline waters, including lithium chloride (LiCl) solutions used in liquid desiccant air-conditioning (LDAC) systems. In this study, the regeneration of liquid desiccant LiCl solution by a pilot direct contact membrane distillation (DCMD) process is assessed using computer simulation. Unlike previous experimental investigations, the simulation allows to incorporate both temperature and concentration polarisation effects in the analysis of heat and mass transfer through the membrane, thus enabling the systematic assessment of the pilot DCMD regeneration of the LiCl solution. The simulation results demonstrate distinctive profiles of water flux, thermal efficiency, and LiCl concentration along the membrane under cocurrent and counter-current flow modes, and the pilot DCMD process under counter-current flow is superior to that under cocurrent flow regarding the process thermal efficiency and LiCl concentration enrichment. Moreover, for the pilot DCMD regeneration of LiCl solution under the counter-current flow, the feed inlet temperature, LiCl concentration, and especially the membrane leaf length exert profound impacts on the process performance: the process water flux halves from 12 to 6 L/(m2·h) whilst thermal efficiency decreases by 20% from 0.46 to 0.37 when the membrane leaf length increases from 0.5 to 1.5 m.

N,S-TiO2 deposited on three kinds of pre-treated sugarcane bagasse was synthesized via a sol–gel method. The obtained composites were characterized by various techniques, including scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and photoluminescence spectroscopy (PL). UV-visible induced degradation of ciprofloxacin was investigated. The influence of some experimental parameters such as contact time, pH, dosage, and initial concentration on the efficiency of ciprofloxacin elimination was also evaluated. The highest efficiency was observed for the alkaline pre-treated sugarcane bagasse combined with N,S-TiO2, about 86% under optimal conditions (contact time 150-min irradiation, pH 5.5–6, dosage 0.5 g L−1, and the initial concentration CIP 30 ppm). There may be a rapid ciprofloxacin transition from the adsorption site to the photocatalytic site, and the alkaline pre-treated sugarcane bagasse/N,S-TiO2 prevented the recombining of holes and electrons of the photocatalyst. Furthermore, the alkaline pretreatment sugarcane bagasse/N,S-TiO2 composite material was sustainable, with only a 10% reduction after reusing the material three times. The presence of sugarcane bagasse made the material easy to recover from the liquid phase.

Fixed-film biofilm reactors are considered one of the most effective wastewater treatment processes, however, the cost of their plastic bio-carriers makes them less attractive for application in developing countries. This study evaluated loofah sponges, an eco-friendly renewable agricultural product, as bio-carriers in a pilot-scale integrated fixed-film activated sludge (IFAS) system for the treatment of municipal wastewater. Tests showed that pristine loofah sponges disintegrated within two weeks resulting in a decrease in the treatment efficiencies. Accordingly, loofah sponges were modified by coating them with CaCO3 and polymer. IFAS pilot tests using the modified loofah sponges achieved 83% organic removal and 71% total nitrogen removal and met Vietnam&rsquo, s wastewater effluent discharge standards. The system achieved considerably high levels of nitrification and it was not limited by the loading rate or dissolved oxygen levels. Cell concentrations in the carriers were twenty to forty times higher than those within the aeration tank. Through 16S-rRNA sequencing, the major micro-organism types identified were Kluyvera cryocrescens, Exiguobacterium indicum, Bacillus tropicus, Aeromonas hydrophila, Enterobacter cloacae, and Pseudomonas turukhanskensis. This study demonstrated that although modified loofah sponges are effective renewable bio-carriers for municipal wastewater treatment, longer-term testing is recommended.

The development of Industrial Zones in Vietnam will put pressure on water resources at local as well as national scale, due to the large amounts of water consumed and discharged to environment. This study, via water mass balance, provides analyses and assessments on water demand and wastewater generated in each trading groups (industrial sectors) of the Long Thanh Industrial Zone and the Nhon Trach III Industrial Zone phase 2, Dong Nai – the province with the most industrial zones in Vietnam. According to the water mass balance calculation results, the water demand of industrial sectors depends on their manufacturing characteristics. Of which, Textile and Garment are the sectors with the highest demand, as well as highest water loss rate and highest amount of wateswater dischared. Meanwhile, Electronic and Construction Materials cosume the least amount of water. Machinery sector has the lowest amount of water loss. The wastewater/supply water ratio of the Long Thanh Industrial Zone is always 1,1 (for Textile) to 1,5 (for Machinery) times higher than the Nhon Trach III Industrial Zone phase 2, while the wastewater/supply water ratio of the Nhon Trach III Industrial Zone phase 2 is always less than 80%.

This study was conducted to assess the removal of arsenic (As) and heavy metals from mining wastewater by the combination of adsorption, using modified iron-ore drainage sludge, and horizontal-subsurface-flow constructed wetland with common reed (Phragmites australis). The pilot-scale experiment with a constant flow rate of 5 m3/day was operated for four months using real wastewater from a Pb&ndash, Zn mine in northern Vietnam. Atomic absorption spectroscopy was used for elemental analysis in wastewater and plant. X-ray diffraction (XRD), surface charge measurements (by a particle charge detector (PCD)), Fourier-transform infrared (FTIR), and surface area Brunauer&ndash, Emmet&ndash, Teller (BET) measurements were performed to determine the characteristics of the adsorbent. The results showed that the average removals of As, Mn, Cd, As, Zn, and Pb by the combined system with limestone substrate during four months were 80.3%, 96.9%, 79.6%, 52.9%, and 38.7%, respectively. The use of another constructed wetland substrate, laterite, demonstrated better removal efficiency of As than limestone. The concentrations of As and heavy metals in the effluent were lower than the limits established by the QCVN 40:2011/BTNMT for industrial wastewater, which indicated the feasibility of combining adsorption and constructed wetland for the treatment of mining wastewater.

Additives used in food pose a risk to consumers' health, and cyclamate is one of the chemical sugars. In this study, cyclamate content in 38 food samples including beverage, cake, candy, milk, and juice was analyzed using Ultra-Performance Liquid Chromatography, Tandem Mass Spectrometry (UPLC-MS/MS). The optimal parameters of detector MS/MS for anion mode; the liquid chromatography column UPHR(R) BEH C18 2.1x100mm 1.7μm, waters, USA; mobile phase: MeOH:H2O (50:50) including 1% HCOOH, deionized water. The ultimate test sample which passed 0.2 μm membrane filter results in retention time: 4.05 minutes, and flow rate of 0.2 mL/min. The quantitative and confirmable ions are 79.7 and 177.9 m/z, respectively. Under the optimum conditions the calibration curve for cyclamate was linear in the range of 5-100 mg/L m with R2= 0.9955, LOD 2.92 mg/kg; LOQ 9.72 mg/kg, bias found 0.015 %, RSD 0.22; recovery ranged 83.38 to 93.40%. The results showed that 23/38 food product samples from markets and supermarkets in Hanoi city contained cyclamate, accounting for 62.53%, with concentrations ranging from 10.9 to 178.1 mg/kg. However, the content of cyclamate in all samples have met the standards as regulated in Circular No. 08/2015/TT-BYT. In addition, cake and candy samples used cyclamate more frequently compare to other analyzed food types.

The incredible growth of plastic waste is a major concern for the whole society in recent years. The accumulation of plastic waste has badly effects on wildlife, habitat, and humans. Plastics that act as pollutants are categorized into different sizes, from micro to macro. Disposable plastic waste was collected at the bakery shop and removed the residue food by tap water and NaOH 1M to remove residual food. This study focuses on modify waste plastic by sulfuric acid to bind the sulfonated function group on the structure of the polystyrene chain at room temperature. The sulfonated product was used for removing heavy metal ion in water with the mechanism of the ion exchange process. The prepared ion exchange material was characterized by FTIR and SEM to ensure that the sulfonation process has happened. The chromium (III) ion removal by modified ion exchange product in continuous mode was affected by an operational parameter such as the bed height of sulfonated material. The Yoon-Nelson and Thomas model were used to analyze the experimental result and the model parameters were evaluated. From this result, it can be concluded that with the increasing amount of sulfonated waste polystyrene, exchange capacity, and the time required for a 50% adsorbate breakthrough was higher.

This study aimed to identify the effects of a low cost polycation, i.e., polyDADMAC (PD), on the aggregation of newly formed Fe oxides. An evaluation was performed over a wide range of pH values and PD concentrations using combined zeta potential and aggregation measurements. PD adsorbs on the surface of the newly formed Fe oxides, altering their surface charge to less negative values, favouring colloidal aggregation. In the absence of PD, aggregation of the newly formed Fe oxides was favoured in a narrow pH range (i.e., 5–6), whereas the presence of PD resulted in faster aggregation over the entire pH range of 3 to 11. In general, PD showed more obvious efficacy at alkaline pH values, and its performance decreased at pH

The ability of the agricultural residue of sugarcane bagasse to serve as an absorbent material used to remove Ciprofloxacin, one of strong Fluoroquinolone antibiotic from aqueous solutions in fixed-bed columns was investigated. The properties of biochar sugarcane bagasse were characterized using scanning electron microscopy (SEM), and Fourier transform infrared (FTIR) spectroscopy before and after modification. The results of fixed bed column experiment showed that the shape of the removal efficiency of CIP and exhaustion time was dependent on bed height, flow rate and initial concentration. The maximum adsorption capacity qo predicted from Thomas modelreached 0.955mg/g at the flow rate of 1mL/min, initial concentration of 15mg/L and bed height of 6cm. From Yoon-Nelson equation, 3.38 minutes was the time required for 50% exhaustion of 12cm bed height column with the flow rate 2mL/min and concentration 15mg/L. Thomas and Yoon-Nelson models were in good agreement with the experimental breakthrough curve data.

PolyDADMAC (PD) is a high charge density cationic polymer of diallyldimethylammonium chloride which has been recently developed as a coagulant in water purification. As PD has high affinity to fine negatively-charged colloids, it is worth to ascertain if PD can affect surface properties of clay-size particles in red mud waste and be applied to develop immobilization techniques for red mud storage areas. In the current study, a test tube method in combination with surface charge measurement was used for determination of the colloidal properties of a red mud sample under the variation of PD, soluble Al and Si, and variable pH conditions. Observations for the PD concentration range from 0.25 to 2.0 mM revealed that PD can increase surface charge and enhance aggregation or at least shift the aggregation zone to higher pH. This suggests a possible application of PD for immobilization of red mud in alkaline condition. It was also found that soluble Al and Si acted to modify the effect of PD and aggregation properties of red mud. While soluble Si supported aggregation, Al appeared as an enhancer for dispersion of red mud. It implies that development of PD-based techniques for immobilization of red mud needs to consider the effects of soluble Al and Si.

Over the last decade, research has been conducted to investigate the use of triboluminescence (TL) as the active element for impact sensors. TL is defined as the emission of light produced by mechanical action. For the last decade, the authors has obtained extensive experience in characterizing TL and has successfully measured it during impacts with speeds of 1 m/s to about 5.6 km/s. For the most part, zinc sulfide and europium dibenzoylmethide triethylammonium (europium tetrakis) compounds have been used as sample materials, since both emit strong TL. Recent ballistic results also show there is a ~1 nm shift in the triboluminescent peak wavelength between the high speed 30 caliber and low speed 9 mm projectiles augmented with ZnS:Mn powder. In fact, the 9 mm peak wavelength for triboluminescence is similar to what was found in earlier measurements. More significantly, collected results also show that the triboluminescent emission yield for ZnS:Mn appeared to be a function of speed for collisions up to 6 km/s using a two-stage light gas gun. These research programs expanded the knowledge base for using TL as the active element for sensors to detect high-speed impacts.