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The diffusive gradients in thin films (DGT) technique serves as a passive sampling method, inducing analyte transport and concentration. Its application is widespread in assessing labile components of metals, organic matter, and nutrients across various environmental media such as water, sediments, and saturated soils. The DGT devices effectively reduce the porewater concentration through irreversible binding of solutes, consequently promoting the release of labile species from the soil/sediment solid phase. However, the precise quantification of simultaneous adsorption and desorption of labile species using DGT devices alone remains a challenge. To address this challenge, the DGT-Induced Fluxes in Soils and Sediments (DIFS) model was developed. This model simulates analyte kinetics in solid phases, solutions, and binding resins by incorporating factors such as soil properties, resupply parameters, and kinetic principles. While the DIFS model has been iteratively improved to increase its accuracy in portraying kinetic behavior in soil/sediment, researchers' incomplete comprehension of it still results in unrealistic fitting outcomes and an oversight of the profound implications posed by kinetic parameters during implementation. This review provides a comprehensive overview of the optimization and utilization of DIFS models, encompassing fundamental concepts behind DGT devices and DIFS models, the kinetic interpretation of DIFS parameters, and instances where the model has been applied to study soils and sediments. It also highlights preexisting limitations of the DIFS model and offers suggestions for more precise modeling in real-world environments. [Display omitted] • DGT technology reveals the kinetic processes of pollutants in soil or sediment. • DIFS model reflects the reservoir and resupply rate of labile analytes. • The limitations and correction approaches of the DIFS model should be considered. [ABSTRACT FROM AUTHOR]

• The g-C3N4/TiO2 heterojunction nanoparticles are firmly immobilised on PAA/PTFE UFM. • The g-C3N4/TiO2/PAA/PTFE UFM shows superb hydrophilicity, anti-fouling and water flux. • Exceptional visible-light regeneration of the fouled g-C3N4/TiO2/PAA/PTFE is demonstrated. • The enhanced anti-fouling and photocatalytic self-cleaning mechanisms are reasonalised. Membrane fouling due to superhydropobicity of polytetrafluoroethylene ultrafiltration membranes (PTFE UFMs) represents a grand challenge for their practical applications in diverse water treatment industries. Surface immobilisation of hydrophilic and chemically stable inorganic metal oxides (TiO 2 , ZrO 2 , etc) has been developed to improve hydrophilicity of the PTFE UFMs, though they still suffer from expensive and repeating regenerations once fouled. To address such issues, we strive to firmly immobilize g-C 3 N 4 modified TiO 2 (g-C 3 N 4 /TiO 2 , hereafter CNTO) onto PTFE UFM via a facile plasma-enhanced surface graft technique using polyacrylic acid (PAA) as a bridging agent. As reported here, the obtained CNTO/PAA/PTFE UFM shows much smaller surface water contact angle (WCA) of 62.3° than that of bare PTFE UFM(115.8°), leading to enhanced water flux of 830 L m−2 h-1 in the initial ultrafiltration of modelled waste-water containing methylene blue (MB). The CNTO/PAA/PTFE UFM is highly resistant to fouling in the prolonged filtration of 1000 mg/L bovine serum albumin (BSA) solution, while the fouled CNTO/PAA/PTFE UFM is able to regenerate rapidly under either UV or visible-light irradiation. The enhanced performance of the novel CNTO/PAA/PTFE UFM is reasonably attributed to its high wettability and robust photocatalytic activity of the g-C 3 N 4 /TiO 2 coating that follows different self-cleaning mechanisms under UV and visible light irradiations. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Amino-MIL-101(Al/Fe) MOFs was applied in high strength phosphate adsorption. • Fast kinetics, high sorption capacity and strong selectivity were demonstrated. • Electrostatic attraction and ligand exchange were identified as the main mechanisms. Abstract Although adsorbents for phosphate removal from eutrophic water have been widely explored, it remains a critical challenge to develop robust and highly selective phosphate adsorbents featuring abundant binding sites and high affinity. In this work, two stable metal-organic frameworks (MOFs) of amine functionalized MIL-101 based on trivalent metal aluminum and iron were synthesized by simple solvothermal methods and applied as adsorbents to capture phosphate ions of high strength. Phosphate adsorption kinetics, isotherm behavior, and solution matrix effects (eg. solution pH, coexisting ions and ionic strength) were reported. Results showed that trivalent metal based NH 2 -MIL-101 MOFs outperformed most adsorbents ever reported, exhibiting fast kinetics and high maximal adsorption capacity above 79.414 mg P/g at 298 K, pH independence in the range from 3 to 11, less sensitivity to ion strength, strong selectivity for phosphate in presence of competing ions and could be easily regenerated and re-applied for phosphate removal. It was noticeable that phosphate adsorption performance varied on the two kinds of trivalent metals based MOFs due to their difference in morphology, surface and interface properties including zeta potential, chemical affinity toward target anion and the types of complexation formed with phosphate. NH 2 -MIL-101(Al) showed faster kinetics, while NH 2 -MIL-101(Fe) has higher affinity toward phosphate. Furthermore, based on Fourier transform infrared (FTIR), X-ray photoelectron spectroscopy (XPS) spectra and zeta potential analysis, electrostatic attraction and ligand exchange were identified as the main phosphate adsorption mechanisms by NH 2 -MIL-101(Al/Fe). Besides, the functionalized adsorbents with amine group further enhanced the phosphate removal capacities by providing extra surficial positive charges. These findings demonstrate that trivalent metal based NH 2 -MIL-101 is a promising candidate for phosphate adsorption from aqueous solution with high efficiency and selectivity. [ABSTRACT FROM AUTHOR]

Surface hydrophilic modification of polymer ultrafiltration membrane using metal oxide represents an effective yet highly challenging solution to improve water flux and antifouling performance. Via plasma-enhanced graft of poly acryl acid (PAA) prior to coating TiO 2 , we successfully fixed TiO 2 functional thin layer on super hydrophobic polytetrafluoroethylene (PTFE) ultrafiltration (UF) membranes. The characterization results evidenced TiO 2 attached on the PTFE-based UF membranes through the chelating bidentate coordination between surface-grafted carboxyl group and Ti 4+ . The TiO 2 surface modification may greatly reduce the water contact angle from 115.8° of the PTFE membrane to 35.0° without degradation in 30-day continuous filtration operations. The novel TiO 2 /PAA/PTFE membranes also exhibited excellent antifouling and self-cleaning performance due to the intrinsic hydrophilicity and photocatalysis properties of TiO 2 , which was further confirmed by the photo-degradation of MB under Xe lamp irradiation. [ABSTRACT FROM AUTHOR]

A nearly 100% filling of PEDOT in TiO 2 nanotube array (NTA) was successfully prepared by a simple electropolymerization method at a constant potential of 1.8 V, which was demonstrated by field emission scanning electron microscopy (FESEM). UV–vis diffusion reflection spectroscopy (DRS) revealed that the filling of PEDOT in TiO 2 NTA can dramatically improve the visible-light and near-infra-red absorption property of the TiO 2 NTA, which is especially useful for the application of solar cells. Cyclic voltammetry experiments indicate that the PEDOT–TiO 2 NTA hybrid material is electrochemically more active than the TiO 2 NTA and has excellent redox reversibility. [ABSTRACT FROM AUTHOR]

Abstract: Anaerobic digestion of Taihu blue algae was tested in laboratory scale, continuous feed digesters (hydraulic retention time 10days) at 35°C and various organic loading rates (OLR). The methane production and biomass digestion performed well at OLR below 4.00gVSL−1 d−1 but deteriorated as OLR increased due to the increased ammonia concentration, causing inhibition mainly to acetate and propionate degradation. Supplementing corn straw as co-feedstock significantly improved the digestion performance. The optimal C/N ratio for the co-digestion was 20:1 at OLR of 6.00gVSL−1 d−1. Methane yield of 234mL CH4 gVS−1 and methane productivity of 1404mL CH4 L−1 d−1 were achieved with solid removal of 63%. Compared with the algae alone, the methane productivity was increased by 46% with less accumulation of ammonia and fatty acids. The reactor rate-limiting step was acetate and propionate degradation. [Copyright &y& Elsevier]

Carbazole-based bisboronic acids were found to be enantioselective fluorescent sensors for tartaric acid. The fluorescence response toward the enantiomers of tartaric acid at neutral pH displayed enhancement/diminishment. The sensor displays an unusual fluorescence intensity-pH relationship with diminished emission at acidic pH but enhanced emission at basic pH. Photoinduced electron transfer (PET) from the fluorophore to the protonated amine/phenylboronic acid unit is proposed to be responsible for this effect, which is rationalized by density functional theory (DFT) calculations. [ABSTRACT FROM AUTHOR]

Abstract: 1,10-Fused ring phenothiazines were found to be a new kind of fluorescent dyes that strongly fluorescence in protic solvents than in aprotic solvents, with higher fluorescence quantum yields (Φ) and longer emission wavelength than the previously reported dyes that with similar solvent sensitivity profile. For example, compound 5 shows a Φ-value of 0.075 in diethyl ether and 0.517 in methanol. Interestingly, a transition from Cbond (5) to Cbond (4) in the fused ring switch the photophysical properties completely, i.e. the analogue compound 4 demonstrates the opposite sensitivity, for which Φ =0.099 in diethyl ether but the fluorescence is quenched completely in methanol. Further derivatization of 5 is convenient, demonstrated by the preparation of compound 6, for which the unique solvent sensitivity is reserved and higher Φ in protic solvents was observed (Φ =0.739 in methanol). The solvatochromism of the compounds were analysed with Lippert–Mataga correlation, values and multilinear regressions with Catalán and Kamlet–Taft solvents scales. The aprotic and protic solvents appeared as two isolated domains in the Lippert–Mataga plots, whereas fitting with scales gives a linear regression comprising both aprotic and protic solvents. Kamlet–Taft scales are more appropriate than the Catalán solvent scales for describing the solvatofluorochromism of the compounds. An intermolecular hydrogen bonding mechanism is proposed for the observed switching of the fluorescence with protic solvents. [Copyright &y& Elsevier]

• An electrode based on MOF-derived Al/C was developed for phosphate removal. • Al/C prepared by two-step calcination showed a stable and conductive structure. • The electrode affords a maximum adsorption capacity of 97.73 mg P/g for 1 V condition. • The electrode could be directly separated from the treated wastewater. • The desorption efficiency reached 89% in 20 min. Porous metal-organic frameworks (MOFs) have drawn increasing attention as promising phosphate adsorbents. Yet the potential agglomeration of MOFs particles and the difficult collection process largely thwarted their application. Meanwhile, adsorbents regeneration might destroy MOFs structures due to the use of strong alkaline solution. In this work, we reported a strategy for designing and fabricating an electrode to remove phosphate based on MIL-101 derived metal/carbon via a two-step carbonization step, which not only introduced C doping but also created a stable structure. With the assistance of electric field, the migration and capture of phosphate anions were greatly enhanced. Under 1 V condition, the material exhibited a high maximum removal capacity of 97.73 mg P/g. Adsorption kinetics and parameters for phosphate at different conditions were analyzed. Langmuir and Freundlich isotherms were employed to validate the adsorption data. More importantly, the regeneration of electrode was achieved in a more facile and efficient way than micro/ nanoparticles adsorbents by simple voltage control. Such an intriguing approach may provide a new platform to further expand the use of MOFs for adsorption process. Image, graphical abstract [ABSTRACT FROM AUTHOR]

Throughout rural regions, large amounts of domestic wastewater are discharged into natural bodies of water without treatment. A well‐designed subsurface wastewater infiltration (SWI) system is an effective wastewater pollution removal strategy for small and remote communities due to its low energy consumption, low operational cost, and good performance. This paper describes the types of structures and purification mechanisms of SWI systems, focusing on the design of substrate materials and the optimization of different operation modes including the hydraulic loading rate, pollutant loading rate, intermittent operation, aeration, and shunting distribution. The challenges and trends in the development of SWI systems are also discussed. Practitioner points: The construction and purification mechanisms of SWI system are described.The design of substrates and the optimization of operation modes are focused.The challenges and the development trends for the system are further introduced. [ABSTRACT FROM AUTHOR]

An advanced biological water purification product Novel Mass Bio System (MBS) with 2–5 mm side length and 1.02–1.08 specific gravity was employed in this study to treat high concentrations of ammonia nitrogen in comprehensive industrial wastewater. MBS is a cubic particle mixed in a proper ratio of microbial liquid, bamboo powdered activated carbon and waterborne polyurethane gel. The comparison experiment between MBS and Moving Bed Biofilm Reactor (MBBR) carrier demonstrates that using MBS is advantageous due to better removal rate of ammonium nitrogen (NH 4 + -N) 95% and total nitrogen (TN) 90%, while MBBR removal rate of NH 4 + -N 80% and TN 75%, respectively. The study examined the feasibility of using Novel Mass Bio System and Anoxic/Oxic treatment process for advanced treatment of comprehensive industrial wastewater having high NH 4 + -N. The experimental results showed that this system could effectively deal with high concentration of NH 4 + -N, chemical oxygen demand (COD), TN removal and remain in a stable level when the operational parameters altered. The excellent performance was obtained at an HRT of 24 h. With an influent average concentration of NH 4 + -N 623–642 mg/L, TN 675–712 mg/L, and COD 1012–1124 mg/L, the effluent NH 4 + -N, TN, COD, could be decreased to 10 mg/L, 80 mg/L and 50 mg/L, respectively. The maximum removal efficiencies of NH 4 + -N, TN, and COD were respectively 98%, 88%, and 95%. Dosing with MBS can effectively improve the removal rate of NH 4 + -N, and carrier additive is simple. It is suitable for the old plants as the effluent can meets strict regulatory requirements for discharge level without the reconstruction of the tank. Therefore, the MBS is a non-toxic and promising cleaner technology for advanced treatment in engineering applications. [ABSTRACT FROM AUTHOR]

Hydrous lanthanum oxide was loaded onto the surface of Fe 3 O 4 @SiO 2 core/shell magnetic nanoparticles to obtain an easily separable adsorbent (abbreviated as Fe–Si–La) for efficient separation of phosphate from water. Fe–Si–La was characterized with XRF, XRD, TEM, specific surface area and magnetization and their performance for phosphate removal was investigated. The Fe 3 O 4 @SiO 2 core/shell structure was confirmed and the hydrous lanthanum oxide was successfully loaded onto its surface. The newly developed adsorbent had magnetization of 51.27 emu/g. The Langmuir adsorption capacity of phosphate by Fe–Si–La reached 27.8 mg/g by loading only 1 mmol lanthanum per gram of magnetite. The adsorption was fast; nearly 99% of phosphate could be removed within 10 min. The removal of phosphate was favored within the pH range 5.0–9.0. The adsorption on Fe–Si–La was not significantly influenced by ionic strength and by the coexistence of the anions of chloride and nitrate but sulfate, bicarbonate and humic acid showed slightly greater negative effects. Phosphate removal efficiency of higher than 95% was attained for real effluent of a wastewater treatment plant when the dose of adsorbent was >0.2 kg/ton. The results showed that adsorbed phosphate could be nearly completely desorbed with NaOH solution for further use. In conclusion, Fe–Si–La is a promising adsorbent for the removal and recovery of phosphate from water. [ABSTRACT FROM AUTHOR]

Abstract: CdTe and ZnS quantum dots sensitized TiO2 nanotube array photoelectrodes were prepared by depositing CdTe and ZnS QDs on the tube walls of the self-organized TiO2 NTs using successive ionic layer adsorption and reaction (SILAR) technique. The deposition of CdTe and ZnS on the upper and inner surface of the TiO2 NTs was confirmed by field emission scanning electron (FE-SEM) and transmission electron microscopes (TEM). The obtained results indicated that TiO2 NTs photoelectrodes sensitized by CdTe quantum dots for 5 cycles exhibited excellent photoelectrochemical properties, with an open-circuit voltage of 0.95V and a short circuit current density of 11.15mAcm−2, and ZnS coating protected the photoelectrodes against photocorrosion. [Copyright &y& Elsevier]

Abstract: With the goal to develop a coal fly ash-based versatile material toward a broad range of pollutants in water, a zeolite (ZFA) was synthesized from coal fly ash and subsequently modified by chitosan. The chitosan modified zeolite (CMZFA) was examined for its capability to sequester cationic (ammonium), anionic (phosphate) and organic (humic acid) pollutants from water. The cation exchange capacity in the internal pores was regarded as the retention capability for cationic ammonium. From the difference between the total and external cation exchange capacity, it was estimated to be 0.90mmol/g (16.2mg/g). Results showed an improved adsorption of CMZFA for phosphate when compared with ZFA, and a maximum adsorption capacity of 4.05mg/g was obtained for CMZFA from the Langmuir model. Though ZFA presented little affinity for humic acid, modification by chitosan largely enhanced the adsorption performance with a Langmuir maximum of 31.6mg/g. The negative charge in the internal pores of zeolite, the oxides of CaO, Al2O3 and Fe2O3 in the non-zeolite fraction, and the monolayer chitosan on the external surface of zeolite were interpreted as the binding bodies for the retention of cationic ammonium, anionic phosphate, and organic humic acid, respectively. [Copyright &y& Elsevier]

Centrifugal mother liquid (CML) is a typical poorly biodegradable organic wastewater generated during the production of polyvinyl chloride (PVC). A method of treating PVC centrifugal mother liquid by a high efficiency internal circulation aerobic biofilm reactor (four reactors lined up together) is presented in this study. The optimized technique was tested and evaluated in a lab and in a plant scale system. The effect of chemical oxygen demand (COD) removal efficiency was studied under different hydraulic retention time (HRT): 40, 20, 17, 14 and 12 h, respectively. Considering the efficiency and removal rate, the best HRT was 14 h. At HRT of 14 h, the average volume loading was 0.326 kg COD/(m 3 ∙d). During the product shift from TL-1000 to TL-800 (two kinds of PVC products with different polymerization degree), the treatment efficiency of the system was not affected. Compared with the plant scale system, the results showed that in the lab setup the removal rates of centrifugal mother liquid of TL-1000 (total organic carbon (TOC) = 70–75 mg/L) and TL-800 (TOC = 20 mg/L) were 90%–95% and 80%–90%, respectively. While in the plant scale system, the removal rates of centrifugal mother liquid of TL-1000 and TL-800 were 80%–90% and 65%–80% (effluent TOC 7.5–12 mg/L), respectively. Biofilm formation by the microbial reproduction as well as intensive filamentous bacteria settlements were observed. [ABSTRACT FROM AUTHOR]

Abstract: The Ag and CdS nanoparticles co-sensitization of TiO2 nanotubes (CdS–Ag/TiO2 NTs) were prepared by successive ionic layer adsorption and reaction (SILAR) technique. The phase composition, morphology and optical property were characterized by the X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and UV–vis diffusion reflection spectroscopy (DRS). The co-modification of Ag and CdS nanoparticles expanded the photoresponse range of TiO2 NTs from ultraviolet region to 668.7nm, and the CdS–Ag/TiO2 NTs prepared by SILAR deposition of 5 cycles exhibited higher visible photocurrent and stability against photocorrosion. The detailed electrons transfer mechanism of CdS–Ag/TiO2 NTs was proposed, and photocatalytic activity toward degradation of methyl orange (MO) under visible-light irradiation was also investigated. [Copyright &y& Elsevier]

Investigation on a full-scale UASB treating industrial wastewater at a low organic loading rate (OLR) was conducted. Excellent treatment performance was achieved when treating the evaporator condensate of distillery wastewater at the OLR of less than 1kgCOD/m3 d. Anaerobic effluent could be discharged without further treatment, which saved energy and running cost considerably. GC–MS analysis showed that the soluble microbial products (SMPs) were decreased to a low level at the low OLR. The main SMP in the anaerobic effluent were long chain carbohydrates and esters, accounting for 55–65% of the total organic matters. Anaerobic SMP was more complex than the aerobic ones. Soluble COD, protein and polysaccharide showed an obvious decrease at the sludge layer from 10 to 15m despite the low MLSS/MLVSS content. Methanogens were found to be predominant in this layer, which indicated that the methanogens might be the main consumers of the SMP in anaerobic reactors. Economic comparison confirmed that the anaerobic treatment at low OLR could be a good option. [Copyright &y& Elsevier]

[Display omitted] • A macroporous MF-HA was prepared via a facile adsorbing method for phosphate removal. • MF-HA could effectively adsorb phosphate over a wide pH range with high selectivity. • Phosphate of 3 mg P/L could be reduced to 0.0015 mg/L. • MF-HA could be easily separated after adsorption with good recyclability. • The cost-efficient raw materials and simple engineering improved its practicality. Effective removal of phosphate from aqueous solution is of great significance in environmental protection. In this paper, the concept of developing a hierarchical and cost-effective aluminum functionalized melamine foam (MF) as phosphate adsorbent is presented. The material with 3D interconnected network, flexibility and ultralow density was fabricated via a simple adsorbing method based on hydrate aluminum and commercially available MF sponge. For use as an adsorbent, performance of the as-prepared MF-HA sponge was assessed with various pH, temperatures, adsorption time, initial P concentrations, ionic strengths and co-existing ions. The experimental results demonstrated that MF-HA performed well in a wide pH range of 4–10 and in the presence of foreign anions, with high maximum uptake capacity of 36.21 mg P/g. Furthermore, for the as-prepared material, the phosphate removal performance at different temperatures established the endothermic nature of the adsorption process. Moreover, MF-HA sponge could be directly separated from the solution and showed a satisfactory recyclability. The adsorbing strategy to design and fabricate the novel sponge with resultant high adsorption efficiency, cost-effectiveness, preferable selectivity, environmental friendliness, and easy separation from water may promote sponge functionalization for applications in extensive wastewater treatment areas. [ABSTRACT FROM AUTHOR]

[Display omitted] • A macroporous MF-HA was prepared via a facile adsorbing method for phosphate removal. • MF-HA could effectively adsorb phosphate over a wide pH range with high selectivity. • Phosphate of 3 mg P/L could be reduced to 0.0015 mg/L. • MF-HA could be easily separated after adsorption with good recyclability. • The cost-efficient raw materials and simple engineering improved its practicality. Effective removal of phosphate from aqueous solution is of great significance in environmental protection. In this paper, the concept of developing a hierarchical and cost-effective aluminum functionalized melamine foam (MF) as phosphate adsorbent is presented. The material with 3D interconnected network, flexibility and ultralow density was fabricated via a simple adsorbing method based on hydrate aluminum and commercially available MF sponge. For use as an adsorbent, performance of the as-prepared MF-HA sponge was assessed with various pH, temperatures, adsorption time, initial P concentrations, ionic strengths and co-existing ions. The experimental results demonstrated that MF-HA performed well in a wide pH range of 4–10 and in the presence of foreign anions, with high maximum uptake capacity of 36.21 mg P/g. Furthermore, for the as-prepared material, the phosphate removal performance at different temperatures established the endothermic nature of the adsorption process. Moreover, MF-HA sponge could be directly separated from the solution and showed a satisfactory recyclability. The adsorbing strategy to design and fabricate the novel sponge with resultant high adsorption efficiency, cost-effectiveness, preferable selectivity, environmental friendliness, and easy separation from water may promote sponge functionalization for applications in extensive wastewater treatment areas. [ABSTRACT FROM AUTHOR]

• Cheap PPy(Cl) composite selective monovalent anion exchange membrane. • 1.23 mol/L 98.2% HCl from the concentrated brine in coal chemistry industry. • Green utilization using BMSED synthesized RO(SW) and freeze crystallization. Mixed salt from the concentrated brine that contains NaCl and Na 2 SO 4 has been classified as hazardous waste since 2016 in China. This fact created an urgent and tremendous demand to treat these brine promptly. In this paper, we reported a method of using selectrodialysis with the bipolar membrane (BMSED) to reutilize the concentrated brine to produce high-purity HCl, NaOH, and Na 2 SO 4 , which fulfilled the demand above. The selective PPy(Cl) composite membrane, which was able to separate NaCl and Na 2 SO 4 in the concentrated brine, was prepared. The 3.5 μm PPy(Cl) film significantly enhanced the selectivity of the anion exchange membrane (AEM) to chloride ions while sulfate ions were blocked. The BMSED stack with our multilayer PPy(Cl) composite AEM produced 1.23 mol/L HCl with a purity higher than 98.2%. More importantly, the prepared PPy(Cl) composite AEM was not only suitable for brine with a high Cl−/SO 4 2− of 19:1, which was the typical ratio in concentrated brine from the coal chemical industry, but also able to treat the brine with a Cl−/SO 4 2− as low as 1:1, showing superior capability. The effluent of the BMSED we developed, which contained 0.02 mol/L Na 2 SO 4 with the Cl−/SO 4 2− equaling to 1:1, could be further concentrated by reverse osmosis for sea water (RO-SW) and freeze crystallization to obtain Na 2 SO 4 with a high purity accordingly. This reutilization route of concentrated brine was very green because it not only produced no hazardous waste, but also recycled valuable products. Therefore, it was believed a promising application in the coal chemical industry. [ABSTRACT FROM AUTHOR]