Vacuum distillation technology (VDT) for the resourceful disposal of oil-based drilling fluids faced challenges due to its high energy consumption. Herein, a novel (C12H25SO3)3Fe-assisted VDT process was developed to promote oil-water-solid separation and improved thermal desorption efficiency for oil-based drilling fluids disposal. The synthesized (C12H25SO3)3Fe exhibited excellent thermal stability, intrinsic amphiphilicity, and superior catalytic activity coupled with VDT. Compared with commercial C15H24FeO6, C12H25SO3Na and FeCl3 & sdot;6H2O, (C12H25SO3)3Fe demonstrated a superior synergistic effect, reducing viscosity and energy consumption by 32.28 % and 15.54 %, respectively, while decreasing interfacial tension from 12.718 to 5.908 mN/m. The recovered oil primarily consisted of C13-C14 hydrocarbon fractions, indicating that the (C12H25SO3)3Fe-assisted VDT process enabled efficient oil recovery without altering the basic chemical composition. TG-FTIR-GC-MS analysis revealed that the maximum thermal-desorption temperature decreased by 15 degrees C, and activation energy decreased from 7.15 kJ/mol to 6.13 kJ/mol with the addition of (C12H25SO3)3Fe. The synergistic decreases of viscosity, interfacial tension and activation energy indicated that the viscosity-reducing, demulsifying, and catalytic effects of (C12H25SO3)3Fe substantially contributed to energy-saving. This study provides an energy-efficient and environmentally sustainable strategy for oil-based drilling fluids disposal and recycling.

Conventional polyamide nanofiltration (NF) membranes suffer from amorphous structures and broad pore size distributions, limiting pharmaceutical removal efficiency. A sequential interfacial polymerization (IP) strategy was developed with initial formation of a crystalline TpTG(Cl) layer via PTSA-mediated IP using triaminoguanidine chloride (TG(Cl)) and 1,3,5-triformylphloroglucinol (Tp), followed by secondary IP (SIP) with TG(Cl) to enhance structural integrity, narrow the pore size, and tailor membrane charges to boost pharmaceutical rejection. This approach enabled & Aring;ngstrom-scale pore refinement from 0.37 nm to 0.285 nm, and slightly shifted the surface charge from -10.0 mV to -14.8 mV, resulting in dense, defect-free membranes with enhanced selectivity. The optimized TpTG(Cl)-TG(Cl0.5%/20) membrane exhibited markedly improved rejection ratios of 91.5% for Na2SO4, 78.53% for MgSO4, 35.5% for MgCl2, 15.93% for NaCl, and 60.4% for xylose. Compared with the pristine membrane, it also demonstrated substantially higher sulfadiazine rejection (85.02% vs. 24.91%), and superior neutral carbamazepine rejection (64.21% vs. 9.32%), as well as moderately enhanced rejection of positively charged pharmaceuticals, with 27.93% vs. 12.57% for metformin, 45.62% vs. 16.95% for sulpiride, and 32.17% vs. 17.34% for propranolol. Notably, the TpTG(Cl)-TG(Cl0.5%/20) membrane maintained low rejection (similar to 40%) of divalent cations (Ca2+ and Mg2+), while retaining high rejection (similar to 80%) for anionic sulfadiazine and neutral carbamazepine (similar to 60%) in simulated tap water. Mechanistic insights from XPS depth profiling and amine group quantification confirmed that TG(Cl) primarily reacted with surface-accessible aldehyde groups, leading to pore refinement and enhanced charge density. The DSPM-DE model accurately predicted the separation performance, further validating the role of steric, Donnan, and dielectric exclusion mechanisms. This work not only offers a scalable and effective approach for fabricating high-performance NF membranes but also provides fundamental insights into the design of functionalized COF membranes for advanced water treatment applications.

The efficient extraction of lithium from salt lake brines characterized by high Mg2+/Li+ ratios presents a significant challenge in sustainable resource recovery. This study presented a systematic evaluation of six commercial nanofiltration (NF) membranes (GH, GT, NF90, NF270, DK, SelRO). Quantitative analysis revealed a moderate positive correlation between the surface amine group density and the Mg2+/Li+ separation factor (up to 24.6), establishing amine density as a key descriptor for selectivity. Higher amine density yielded a more positive surface charge, which enhanced Donnan exclusion of Mg2+. Membranes exhibiting a positive surface charge (DK, SelRO, GT) achieved superior Mg2+ rejection (>90%) and high separation factors. In particular, the DK membrane exhibited a separation factor of 24.6 at a Mg2+/Li+ ratio of 150, attributable to enhanced Donnan exclusion of divalent cations. Furthermore, the pore size distribution emerged as a critical determinant of selectivity, wherein narrow distributions (e.g., Sp = 0.26 for the GT membrane) significantly enhanced separation precision. The Donnan Steric Partitioning Model with Dielectric Exclusion accurately predicted separation performance (error <15%), identifying volume charge density as the dominant factor. This work established a quantitative correlation between surface amine density and Mg2+/Li+ separation performance, providing practical insights for membrane selection and future membrane design.

Traditional nanofiltration (NF) membranes exhibit low rejection ratios for low-molecular-weight (LMW) or positively charged pharmaceuticals owing to broad pore size distributions and negatively charged surface. Covalent organic frameworks (COFs) are highly promising for membrane fabrication due to their tunable pore functionality and adjustable pore sizes. Herein, dual-charged COF membranes were fabricated via sodium dodecyl sulfate (SDS)-mediated interfacial polymerization (IP), followed by polyethyleneimine (PEI) crosslinking to improve the removal of LMW or positively charged pharmaceuticals. In the SDS-mediated IP process, the reduction of pore size from 0.387 +/- 0.60 nm (COF0-10 membrane fabricated without SDS) to 0.269 +/- 0.54 nm (COF0.25-10 membrane) led to a substantial improvement in Na2SO4 rejection ratio from 43.9 % to 81.4 %. Furthermore, PEI crosslinking with residual free -CHO groups on the COF0.25-10 membrane surface enhanced size sieving and electrostatic interactions while preserving membrane crystallinity. The optimized COF0.25-10-PEI0.2-2.5 membrane with the pore size of 0.209 nm demonstrated exceptional rejection ratios (>87 %) for five representative pharmaceuticals with different properties. Among them, the optimized COF0.25-10-PEI0.2-2.5 membrane showed superior rejection ratio of 92.6 % for the positively charged and LMW (129.16 Da) metformin. Compared to the pristine COF0.25-10 membrane without PEI crosslinking, the resulting COF-PEI membranes demonstrated 3.8-6.5 folds improvement in pharmaceutical rejection, particularly for challenging LMW and positively charged pharmaceuticals, owing to the synergistic effects of size exclusion and electrostatic interactions. Furthermore, mechanistic study revealed that SDS in aqueous phase promoted faster and more uniform diffusion of TG(Cl) monomers, enhancing the crystallinity of the TpTG(Cl)-COF membranes and improving the pore uniformity, while PEI crosslinking further narrowed the pore size and obtained dual- charged COF layer. This study provides a new paradigm for designing charge-tunable and crystalline COF membranes for precision separation of LMW pharmaceuticals.

Membrane fouling, primarily due to organics and particles, significantly impedeed efficient recycling of shale gas produced water (SGPW). This study compared a novel hybrid electrocoagulation (EC) coupled with E-peroxone process (ECP) with other processes (O3, E-peroxone, EC, and ozonation-elecro-coagulation(eHOC)) to evaluate the potential of ECP as a pretreatment for ultrafiltration(UF) fouling mitigation and dissolved organics removal for SGPW recycling. The initial UF flux percentages following treatment with O3, E-peroxone, EC, eHOC, and ECP were 47.5 %, 49.1 %, 81.3 %, 85.5 %, and 89.9 % of pure water flux, respectively. SGPW pre-treated by the ECP process exhibited the highest flux and significant fouling mitigation. TOC removal efficiency of the ECP process was the highest of 60 %, which was approximately 10 % higher than that of eHOC (51.4 %), E-peroxone (48.8 %), and EC (48.8 %), and was substantially higher than O3 (32.3 %). Substantial alleviation of cake filtration was observed after various pretreatment processes. The ECP process was favored due to its relatively high water flux, low TOC (8.38 mg/L) and turbidity in the permeate with the current density of 50 mA/cm2. SEM-EDS analysis revealed that ECP effectively mitigated membrane fouling by removing particles and organics. Consequently, ECP-UF process was highly efficient and space-saving, offering a synergistic effect for UF fouling mitigation for SGPW recycling.

The nanofiltration (NF) membrane with better hydrophilicity, uniform pore size distribution, and dually charged properties is highly desirable to improve the pharmaceutical rejection, especially for the neutral and positively charged pharmaceuticals. Herein, a TpPa membrane was first in-situ crystallized via p-toluenesulfonic acid (PTSA)-mediated interfacial catalytic polymerization (ICP) strategy using 1,3,5-triformylphloroglucinol (Tp) and p-phenylenediamine (Pa), followed by the post-functionalization with polyethylene-imine (PEI) to narrow the pore size, improve hydrophilicity, and tailor membrane charges to enhance pharmaceutical rejection. PTSA was used as a catalyst to enhance the crystallinity of the TpPa membrane. The PEI introduction narrowed the pore radius from 0.382 +/- 0.50 nm to 0.272 +/- 0.33 nm, improved surface hydrophilicity from 74.8 degrees to 37.0 degrees, and shifted surface charge from-19.25 mV to 11.15 mV. This PEI-functionalized TpPa (TpPa-PEI) layers exhibited heterogeneous charges on both sides with a positively charged top and negatively charged bottom. MgCl2 rejection increased from 13.7 % to 83.0 % without sacrificing water permeance. Additionally, pharmaceutical rejection and the water permeance of the optimal TpPa-PEI membrane exceeded those of the TpPaIP-PEI membrane fabricated without PTSA by about 3.3 and 1.3 times, respectively. Furthermore, compared to the pristine TpPa membranes, the substantially enhanced electropositivity of the optimal TpPa-PEI membrane led to 3-5 times increase in positively charged pharmaceutical rejection (94.1 % for propranolol, 97.2 % for sulpiride, and 71.2 % for metformin). The synergy between the negatively charged TpPa-PEI bottom layers and the reduced pore size maintained a sulfadiazine rejection of 62.1 %. Mechanistic study further revealed that PEI penetrated 100 nm into the TpPa layer and cross-linked with the aldehyde groups, leading to tailored chargeability, improved hydrophilicity, and reduced pore size of the membranes. Via a PEI cross-linking strategy, subnanometer channels of crystalline COF layers can be rationally designed, featuring precisely tailored chargeability and hydrophilicity, promising functionalization of the membrane pores and remarkably robust for water reuse.

In this paper, the sewage treatment plant of a petrochemical company in Shaanxi Province was used as the research object to optimize the effect of nitrogen and carbon removal by adjusting the operating parameters of A/O-MBR pilot system, and the mathematical model of sewage biological treatment system based on the activated sludge models(ASMs) was established to simulate the sewage treatment process. The results of operation and debugging showed that the AO5 process still could not ensure the effluent meet the standard after optimizing the operation parameters. Then the residence time of the anoxic zone was extended from 4 h to 8 h by changing the original AO5 process to A2O4 process. Under the conditions of 20% filling ratio in the aerobic tank, 100% sludge reflux in the anoxic tank, and 200% nitrate liquid reflux, effluent COD, NH4+-N, and TN were 28.53 mg/L, 0.24 mg/L, and 12.22 mg/L, respectively, which met the concentration limit standards for other units of water pollutants in Table 2 of the Integrated Wastewater Discharge Standard of Yellow River Basin in Shaanxi Province(DB 61/224-2018). In addition, the Ind. ASM-Petrochem model based on the ASMs model could simulate the removal of COD and NH4+-N accurately, while further improvement was needed for the simulation of TN.

Ionized amine group (R-NH2) and carboxyl group (R-COOH) within the active layer of polyamide (PA) nanofiltration membranes result in the formation of positive (R-NH 3 + ) and negative (R-COO−) functional groups, respectively, which determines membrane performance and is essential for membrane fabrication and modification. Herein, a facile dye adsorption/desorption method using Orange II and Toluidine Blue O dyes was developed to measure the densities of R-NH2, R-NH 3 + , R-COOH, or R-COO− on surfaces of six PA membranes, and the correlation between the density of such groups and the zeta potential was established. The dye adsorption method was proven reliable due to its lower standard deviation, detection limit, and quantification limit values. Furthermore, the densities of R-NH 3 + or R-COO− under different pH values were measured, fitting well with results calculated from the acid-base equilibrium theory. Additionally, a correlation was established between the net surface density ([R-NH 3 + ] − [R-COO−]) and the surface charge density (σ) calculated via the Gouy–Chapman model based on zeta potential results. The resulted correlation (σ/(mC·m−2) = (3.67 ± 0.08) × ([R-NH 3 + ] − [R-COO−])/(nmol·cm−2) + (0.295 ± 0.08)) effectively predicts the σ value of the membrane. This study provides a facile and reliable dye adsorption method for measuring the density of R-NH2, R-NH 3 + , R-COOH, or R-COO−, enabling an in-depth understanding of membrane charge properties.

Fabricating crystalline covalent organic framework (COF) membrane with sub-nanopores for desalination remains challenging. Monomer (p-phenylenediamine (Pa) and 1,3,5-triformylphloroglucinol (Tp)) concentration was crucial to tailor the diffusion-reaction process in the p-toluenesulfonic acid (PTSA)-mediated interfacial catalytic polymerization process for crystalline TpPa-COF membrane fabrication. By increasing monomer concentration, membrane surface color evolved from light yellow to dark orange. TpPa-COF layers with adjustable thickness (90.47-436 nm) transformed from amorphous to crystalline with crystalline and cross-linking degree increasing from 16.47 % to 73.90 %, and 66.40 % to 87.60 %, respectively. Pore size decreased from 1.69 to 0.17 nm, while Na2SO4 rejection significantly increased from 26.7 % to 90.4 %. A 3-day filtration test for RO concentrate demonstrated the stability and robust desalination performance with SO42- rejection ratio of 74.3 +/- 1.08 % and Mg2+ rejection ratio of 65.6 +/- 1.33 %. Diffusion behavior experiments demonstrated that diffusion coefficient for Pa-PTSA complex (6.49 x 10(-5)-8.87 x 10(-5) cm(2) s(-1), Pa > 0.05 wt%) higher than Tp (3.53 x 10(-6)-6.39 x 10(-6) cm(2) s(-1), Tp > 0.006 wt%) by one order of magnitude promoted structural crystallinity and regulated assembly at the interface, resulting in TpPa-COF layer with sub-nanopores. This study highlighted the importance of monomer concentration on the COF membrane formation, providing valuable insights for the highly crystalline COF membrane fabrication.

Membrane fouling caused by the organics-coated particles was the main obstacles for the highly efficient shale gas produced water (SGPW) treatment and recycling. In this study, a novel hybrid electrocoagulation (EC) and E-peroxone process coupled with UF (ECP-UF) process was proposed to examine the efficacy and elucidate the mechanism for UF fouling mitigation in assisting SGPW reuse. Compared to the TMP (transmembrane pressure) increase of −15 kPa in the EC-UF process, TMP in ECP-UF system marginally increased to −1.4 kPa for 3 filtration cycles under the current density of 15 mA/cm2. Both the total fouling index and hydraulically irreversible fouling index of the ECP-UF process were significantly lower than those of EC-UF process. According to the extended Derjaguin-Landau-Verwey-Overbeek theory theory, the potential barriers was the highest for ECP-UF processes due to the substantial increase of the acid-base interaction energy in ECP-UF process, which was well consistent with the TMP and SEM results. Turbidity and TOC of ECP-UF process was 63.6% and 45.8% lower than those of EC-UF process, respectively. According to the MW distribution, the variations of compounds and their relative contents were probably due to the oxidation and decomposing products of the macromolecular organics. The number of aromatic compound species decreased, while the number of open-chain compounds (i.e., alkenes, alkanes and alcohols) increased in the permeate of ECP-UF process. Notably, the substantial decrease in the relative abundance of di-phthalate compounds was attributed to the high reactivity of these compounds with ·OH. Mechanism study indicated that ECP could realize the simultaneous coagulation, H2O2 generation and activation by O3, facilitating the enhancement of ·OH and Alb production and therefore beneficial for improved water quality and UF fouling mitigation. Therefore, the ECP-UF process emerges as a highly efficient and space-saving approach, yielding a synergistic effect in mitigating UF fouling for SGPW recycling.

Construction of covalent organic frameworks (COF) membranes on the polymeric substrate was challenging by interfacial polymerization (IP) process. In this study, COF-LZU1 membranes were fabricated by IP on the pre-heated PSf substrates to investigate the influence of substrate properties (i.e., pore size and porosity) on the COF-LZU1 layer formation. The substrates with tunable pore size (18.61 to 14.53 nm) and porosity (2.05 % to 0.42 %) could be obtained with the pretreating temperature of 20 degrees C to 50 degrees C. Preheated substrate altered monomer storage and diffusion, leading to the variations in crosslinking degree (14.89 % to 87.63 %) and observed thickness (142.9-575.9 nm). The preheated substrates endowed better growth conditions by inhibiting the COF-LZU1 intrusion into the substrates, and optimal COF40 degrees C membrane had water flux of 6.57 L m (2) h (1), and Na2SO4 rejection ratio of 90.9 %. The rejection ratio of pharmaceuticals by COF-LZU1 membranes was low due to adsorption. Correlation analysis showed that the C=N bond content was unfavorable for absorption (P < 0.05), and the increase of crosslinking and crystallinity of the COF-LZU1 layer will be beneficial to boost the pharmaceutical rejection. This work provided a facile method and valuable insight for the COF-LZU1 membrane fabrication to enhance desalination and pharmaceutical removal. [GRAPHICS] .

Electrocoagulation (EC) coupled with E-peroxone process (ECP) offers a promising approach for simultaneous coagulation and oxidation, enhancing contaminant removal efficiency and current efficiency within a single electrochemical system. However, understanding the production characteristics of active species and their synergistic effects remains limited. This study comprehensively investigated the production of active species (i.e., center dot OH and coagulant) during the ECP process and explored their synergistic effect in real water purification. Increasing current density and O3 dosage led to significant enhancements in center dot OH and Alb production. The synergistic factor (beta) for center dot OH production ranged from 1.68 to 1.73 for lower current density and from 1.19 to 1.32 for higher current density, while beta for center dot OH production in ECP increased from 0.77 to 1.16-1.19 with increased O3 dosage. Besides O3 decomposition and cathodically-induced H2O2 production, alternative pathways contributed to enhanced center dot OH production and synergistic effects. The Al-based coagulant facilitated the reaction with O3, initiating a chain reaction for center dot OH and Alb production. Furthermore, the feasibility and synergistic effects of ECP for two water matrices (surface water and shale gas produced water) were compared. ECP exhibited superior performance for both matrices, with TOC removal exceeding 63.2 % for surface water and 87.0 % for shale gas produced water. The study provides deeper insights into the ECP process, highlighting its potential for sustainable water treatment.

Polysulfone (PSf) membranes typically have a negligible rejection of salts due to the intrinsic larger pore size and wide pore size distribution. In this work, a facile and scalable heat treatment was proposed to increase the salt rejection. The influence of heat treatment on the structure and performance of PSf membranes was systematically investigated. The average pore size decreased from 9.94 ± 5.5 nm for pristine membranes to 1.18 ± 0.19 nm with the increase in temperature to 50 °C, while the corresponding porosity decreased from 2.07% to 0.13%. Meanwhile, the thickness of the sponge structure decreased from 20.20 to 11.5 μm as the heat treatment temperature increased to 50 °C. The MWCO of PSf decreased from 290,000 Da to 120 Da, whereas the membrane pore size decreased from 5.5 to 0.19 nm. Correspondingly, the water flux decreased from 1545 to 27.24 L·m−2·h−1, while the rejection ratio increased from 3.1% to 74.0% for Na2SO4, from 1.3% to 48.2% for MgSO4, and from 0.6% to 23.8% for NaCl. Meanwhile, mechanism analysis indicated that the water evaporation in the membranes resulted in the shrinkage of the membrane pores and decrease in the average pore size, thus improving the separation performance. In addition, the desalting performance of the heat-treated membranes for real actual industrial wastewater was improved. This provides a facile and scalable route for PSf membrane applications for enhanced desalination.

Construction of covalent organic frameworks (COF) membranes for desalination applications was challenging, mainly due to the poor crystallinity and large intrinsic pore size of COFs. Herein, the p-toluenesulfonic acid (PTSA)-mediated interfacial catalytic polymerization (ICP) strategy was proposed to fabricate COF membranes with high crystallinity and sub-nano pores on the polysulfone substrate to enhance desalination and selectivity performance. The proposed PTSA-mediated ICP strategy facilitated the amorphous-to-crystalline transformation and regulated the stacking behavior of COF crystals. Via PTSA meditated ICP process, a ribbon-like crystal structure was observed on the membrane surface. The amorphous COF layers with a thickness of 122-412 nm transformed into crystalline COF layers with a thickness of approximately 245-390 nm, while the pore radius of the COF membranes decreased from 0.65-1.25 nm to 0.17-0.25 nm due to the multilayer stacking of COF crystals on the membrane surface. Meanwhile, the crystalline degree of these COF membranes increased from 21.45% to 73.95% with increasing PTSA concentration and ICP time. The optimal TpPa3%-15 membrane had a water permeability of approximately 3.74 L-1 m-2 h-1 bar- 1 and substantial enhancement of Na2SO4 rejection from 19.7% to 90.4%. The 30-day duration of the cross-flow operation measurement demonstrated excellent stability and robust selectivity of SO42- and Cl- for the optimal TpPa3%-15 membrane. In addition, the optimal membrane exhibited excellent desalination performance for divalent ions in petrochemical wastewater and shale gas produced water than that of pristine membrane, rendering their applicability for industrial wastewater desalination. The mechanisms analysis verified that PTSA induced disorder multilayer stacking of crystalline COF crystals on the substrate surface, resulting in reduced pore sizes and increased desalination of the COF membranes. As the traditional IP process, this work proposed that PTSA mediated ICP process was a facile, scalable and time-saving approach for the construction of highly crystalline COF membranes with sub-nanometer pores to achieve enhanced desalination performance.

有机液体存储与调和挥发损失是石油石化行业VOCs排放的典型排放源项和主要管控源.为落实罐区VOCs排放的高效化管控,需基于罐型,探究、识别并归纳不同影响因素变量对储罐VOCs排放源强的作用程度.固定顶罐较内、外浮顶罐更易产生油品损耗和环境污染,故以其为研究对象,基于生态环境部的《石化行业VOCs污染源排查工作指南》所提的有机液体存储VOCs损耗评价模型工具,运用微观情景分析法和控制变量法,探究物料性质、气象条件、年平均储存高度、罐漆颜色和年周转量等影响因素变量下的固定顶罐VOCs损耗变化规律,并根据此规律,提出升级工艺流程及合理分配炼化产品份额、推广使用低挥发性材料且削减高挥发性物料的用量需求和改涂罐壳颜色为白色等专一化、精细化的固定顶罐VOCs排放管控建议.

Holey graphene oxide (HGO) and reduced HGO membranes (rHGO) can overcome high tortuosity and poor stability of GO-based membranes, respectively. In this study, HGO and rHGO membranes were fabricated to try to quantitatively elucidate the etching and reduction time on structure, stability and rejection performance for slat and pharmaceuticals. Water flux of HGO membrane linearly increased (Jv=2.07t + 1.02, R2=0.9931) and Na2SO4 rejection linearly decreased (RNa2SO4=- 4.37t + 88.26, R2=0.9511), while the membranes stability substantially increased with etching time from 1 to 5 h (water flux variation from 22% to 5% and rejection ratio variation from 17% to 7%) under long-term vibration . Subsequently, water flux of rHGO membranes exponentially decreased (Jv=exp(2.89-0.12t + 0.0039t2), R2= 0.9996) with reduction time, while slightly improved salt rejection (RNa2SO4=exp(2.89-0.12t + 0.0039t2), R2= 0.9971) were observed. Effective length of actual pathways for GO, HGO4 and rHGO4-5 membranes calculated by the mass transfer-based model was 7.37 & PLUSMN; 0.47, 4.48 & PLUSMN; 0.68 and 7.23 & PLUSMN; 1.29 & mu;m, respectively, which were much higher than that geometric thickness of the GO membranes. These results indicated that d-spacing, tortuosity and porosity should be comprehensively considered for membrane design and fabrication. With a series of saccharides as probes, average pore size slightly decreased for HGO4 (rp=0.36 nm, Sp=0.34) and rHGO4-5 (rp=0.33 nm, Sp=0.28) membrane compared with GO membranes (rp=0.38 nm, Sp=0.3), demonstrating that etching and following reduction marginally affected the pore size distribution. H2O2 etching increased both water permeability (A) and its selectivity (A/B) for three pharmaceuticals, while the thermal reduction substantially decreased the water flux. Moderate and low rejection ratios for the three pharmaceuticals also demonstrated the importance of trade-off between etching and reduction time and the urgent need for narrowing pore-size distribution for GO-based membranes for water purification.

Stability is a key issue to improve the commercialization of graphene oxide (GO) membranes for aqueous separation. Herein, the effect of dopamine (DA) addition mass on the performance and stability of the DA-mediated GO membranes was systematically investigated. The d-spacing of GO/DA membranes increased from 0.78 to 1.02 nm with DA loading from 0 to 25%. The improvement of water flux for GO/DA membranes was ascribed to the increased hydrophilicity and enlarged d-spacing, but excessive crosslinkers contributed to the declining water flux. The Na2SO4 rejection of GO/DA membranes showed the opposite trend with variations of less than 10%. The 30-day immersed evaluation further validated that the stability of DA-mediated GO membrane improved with increasing DA addition. The spacing modulation and functional groups in the interlayer galleries contributed to the rejection performance and swelling of the GO membranes. The negligible effect of pharmaceutical adsorption on the d-spacing demonstrated the stability of the GO/25%DA membrane. The density functional theory (DFT)-based molecular simulations indicated the GO membranes could be crosslinked by the interaction of polydopamine with the oxygenated groups of GO nanosheets, and the hydration of the residual hydrophilic functional group or the bounded DA monomers of GO was responsible for the slight swelling effect.

氧化石墨烯(GO)是一种理想的二维结构分离膜材料.从GO结构性质入手,探讨了GO混合基质膜和GO层压膜(GO膜)的制备及其在水处理中的研究现状与前景.分析了GO的添加方式对混合基质膜性能的影响,未来需要进一步对GO表面的活性基团进行改性以提高其分散性和与聚合物的相容性,并加强GO及改性GO的添加方式对膜性能影响的研究.GO混合基质膜在一定程度上可克服传统聚合物膜的Trade-off效应,技术成熟度较高、应用前景较好.GO膜在水溶液中的不稳定性是其在水处理中应用中的瓶颈,在系统分析提高GO膜稳定性的方法的基础上,进一步指出需要探讨采用新型交联剂或多种稳定方法同步强化其稳定性的可行性,同时其在实际应用中的稳定性及长期运行效果需要进一步研究和验证,以利于开拓其应用.

高钙镁油藏聚合物驱采出水中高浓度的水解型聚丙烯酰胺(HPAM),易造成常规"隔油-混凝-过滤/气浮"工艺出水水质恶化和滤料堵塞,因此亟须开发高钙镁油藏聚合物驱采出水处理技术与方法.陶瓷膜因其良好的出水水质和抗污染、耐酸碱清洗等优势在油气田废水处理中日益受到重视.基于高钙镁油藏采出水中HPAM浓度高的难题,以提高出水水质和工艺稳定运行为目的 ,研究了化学絮凝和臭氧氧化+化学絮凝预处理对陶瓷膜出水水质和膜污染的影响.结果 表明:HPAM浓度为500 mg/L的模拟采出水经化学絮凝和臭氧氧化+化学絮凝2种预处理工艺,均能有效地减缓陶瓷膜的污染并提高陶瓷膜出水水质,其中臭氧氧化+化学絮凝+陶瓷膜过滤工艺处理后,出水油含量低于10 mg/L,粒径中值＜0.8μm,出水水质符合SY/T 5329-2012《碎屑岩油藏注水水质指标及分析方法》油藏地层空气平均渗透率＞0.05 μm2的要求,说明臭氧氧化+化学絮凝+陶瓷膜工艺处理高聚合物浓度采出水的可行性.

Polyamide (PA) nanofiltration (NF) membranes were fabricated via interfacial polymerization (IP) with graphene oxide (GO)/aminated GO (NGO)-incorporated substrate and then compared for petrochemical wastewater and shale gas produced water desalination. Crosslinking degree of PA layer with GO-incorporated substrate and NGO-incorporated substrate was higher than pristine membrane. Water flux of TFCGO-0.05 (with GO addition mass of 0.05 wt%) and TFCNGO-0.075 (with NGO addition mass of 0.075 wt%) membrane substantially increased by 15.6% and 26.9% with the highest flux of 44.93 and 49.30 L m-2 h-1, respectively, while slight difference was observed for Na2SO4, MgSO4, NaCl rejection. The better performance of TFCNGO than TFCGO was attributed to much thinner PA layer due to relatively larger pore size, higher hydrophilicity, and possible reaction of amino group of NGOs with TMC, which resulted in lower PA layer thickness of TFCNGO membranes. Substantial enhancement of water flux (higher than 24.8%) and similar divalent ion rejections can be observed for petrochemical wastewater, as consistent with the single salt test. However, better performance in permeability and divalent ion rejections (approximately 6% higher than pristine membrane) was observed for shale gas produced water. These results also demonstrated that it is feasible to incorporate NGO into substrate for NF fabrication to improve performance for industrial water desalination.