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The use of resistant rootstocks is an inevitable trend in the development and production of grapes (Vitis sp.). The present study analyzed differences in the metabolites in grape seeds of different rootstock combinations (1103P, 5C, SO4, 3309C, 140R, and control) grafted onto ‘Cabernet Sauvignon’ (CS) wine grape (Vitis vinifera) scions (control, CS/CS, self-rooted grafting vines) using liquid chromatography–mass spectrometry (LC-MS) and nontargeted metabolomic techniques. Principal component analysis (PCA), partial least squares discriminant analysis (PLS-DA), and orthogonal-partial least squares discriminant analysis identified 30 significant metabolites and 22 metabolic pathways in the seeds of CS that differed significantly from the control seeds. This study revealed that rootstocks influence metabolite concentrations and metabolic pathways (alanine–aspartate–glutamate pathway, arginine-proline pathway, and the tricarboxylic acid cycle) in the scion onto which they are grafted. The rootstocks increased the concentration of delphinidin-3-(6-acetylglucoside), peonidin 3-(6-p-coumarylglucoside), L-threonine, and D-tartaric in CS seeds. Appropriate rootstock combinations can be used to improve the quality of grape seeds by changing the concentrations of amino acids, organic acids, polyphenols, and vitamin B. This study provides a theoretical basis for selecting grape rootstocks and provides important insights for improving the quality of commercial products derived from grape seeds.

Membrane fouling during the treatment of produced water containing oil emulsions remains a major technical challenge for the oil and gas industry. Here, we demonstrate the preparation and performance of a fouling resistant hollow fiber membrane using a synthetic saline oil-in-water emulsion. The membrane was prepared by coating commercial polyethersulfone (PES) hollow fibers with a layer of sulfonated polyether ether ketone (SPEEK). The SPEEK coated membrane was significantly more oleophobic than the support PES membrane, possibly due to a non-porous surface, higher hydrophilicity, and more negatively charged SPEEK surface. The SPEEK coated membrane could achieve complete oil rejection without any observable membrane fouling and considerably higher salt, turbidity, and sodium dodecyl sulfate (SDS) rejection than the support PES membrane. An initial increase in water flux was observed with the SPEEK coated membrane. The flux increase observed here could be attributed to the incorporation of SDS molecules into SPEEK polymeric network and subsequent electrostatic interaction amongst charged functional groups leading to conformational changes of the SPEEK layer. Dynamic adsorption and desorption experiments illustrated the interaction between SDS and SPEEK. A strong correlation between the amount of SDS entrapped in the SPEEK polymeric network and water flux was observed. Results from this study illustrated the potential of SPEEK coated membrane as a major breakthrough for oil recovery and wastewater reuse in the oil and gas industry.

Forward osmosis (FO) is a low energy process when recovery of the draw solutes is not necessary. This study focused on the performance of the FO process for concentrating underground brine (UGB) with saturated sodium chloride as draw solution (DS) using two membranes: commercialized flat sheet cellulose triacetate (CTA) membrane and tailor-made thin film composite (TFC) FO membrane. Energy dispersive X-ray spectroscopy (EDS) and powder X-ray diffractometry (XRD) analysis indicate that, majority of the scaling components were calcium sulfate and sodium chloride crystals formed both through surface and bulk crystallization. The spacer in the FO test cell also promoted scaling. Without spacer, a sharp flux decline of TFC membrane occurred at a higher concentration factor while no sharp flux drop was observed for CTA membrane. It was hypothesized that the rough TFC membrane surface may initiate nucleation and aggregation of the crystals in the active surface, and eventually resulting in scaling.

Forward osmosis (FO) is a promising technique for desalinating high salinity wastewaters, and membrane performance is critical for its successful application. In this work, the dehydration of FO membranes was demonstrated for both commercial cellulose triacetate and tailor-made thin-film composite membranes. A significant loss of FO flux was observed after membrane dehydration, but the pure water permeability and rejection properties remained about the same. Dehydrated membrane showed opaque/white spots on the initially homogeneous membrane. Once dehydrated, a membrane with a much lower water flux will be resulting in. It was demonstrated that when the active skin layer was in contact with the saline solution before the support layer was brought into contact with an aqueous solution, membrane dehydration took place. The dehydration was ascribed to osmosis gradient across the active layer that caused water flow from membrane support layer to the active layer, resulting in support dehydration. The dehydrated membrane could be rewetted again by low surface tension liquid or reverse osmosis, illustrating that membrane dehydration is reversible. Precaution should be addressed when operating large FO system to prevent the membrane dehydration for high salinity water treatment.

A polyamide thin-film composite (TFC) forward osmosis (FO) membrane was fabricated and compared to a commercially available cellulose acetate (CTA) membrane for treating shale gas drilling flow-back fluids (SGDFs). The polyamide TFC membrane outperformed its CTA counterpart in terms of pure water flux and reverse salt flux when synthetic brine was used as the feed. More severe fouling was observed for the polyamide TFC membrane as compared to the CTA counterpart when treating SGDF. Very quick buildup of fouling was identified for TFC membrane but not significant for CTA membrane. Ultrafiltration pre-treatment delayed but did not alleviate fouling formation. Surface modification of the TFC membrane by poly(ethylene gycol) (PEG) grafting resulted in reduced membrane fouling and marginal decrease in water flux.

PVDF membranes, after surface modification by CF 4 plasma, have demonstrated surperhydrophobic surface characteristics and up to 30% flux enhancement in direct contact membrane distillation (MD). The heat transport in the MD process was modeled to assess the membrane distillation coefficients ( B m ). The experimentally determined B m showed up to 50% deviation from the modeled values for CF 4 modified PVDF membranes. An effective evaporation factor, as a function of surface porosity and surface water contact angle, was proposed to correlate surface wettability contribution to the MD flux. This factor was fitted by comparing the experimentally determined flux with modeled one. It was found that the factor, which is positively related to surface water contact angle and surface porosity, varied with the membrane wettability and can rationally explain the deviation between observed and theoretical fluxes. In addition, CF 4 plasma modification could increase the membrane׳s evaporation efficiency from 54.3% for the virgin membrane up to 63.4% for surface modified membranes because of the increase of the effective evaporation area factor. The introduction of the factor provides a means to evaluate the membrane surface hydrophobicity to the MD flux and necessitate the development of super even ultra-hydrophobic membranes.

Composite hollow fiber nanofiltration membrane coated with a thin layer of sulfonated poly(ether ether ketone) (SPEEK) can separate monovalent ions from multivalent ions with a low energy demand. It has found applications in desalination of glyphosate wastewater and removal of arsenic from drinking water. Before large scale application of such membranes, one of the main issues is the long time performance stability. This paper reports, for the first time, systematic investigations on the origins of the instability of the SPEEK composite membrane in aqueous phase. Membrane preparation parameters, the coating polymer concentration, the coating time, and the post-treatment temperature were correlated to the membrane stability. A reptation mechanism was proposed to explain the rejection decline and flux increase with time, based on swelling and dissolution of SPEEK. To reduce the swelling and loss of SPEEK, a PVA/SPEEK blend was used as the coating layer, which after cross-linking by glutaraldehyde, yielded a NF membrane with constant rejection during 2000 h of operation.

A new composite hollow fiber nanofiltration (NF) membrane with a thin sulfonated poly(ether ether ketone) (SPEEK) active layer was prepared and used for arsenic removal. The effects of the feed concentration, pH and transmembrane pressure on arsenic removal were systematically examined. The obtained SPEEK hollow fiber NF membrane could achieve an As(V) rejection of over 95% and water permeability of 11 L m−2 h−1 bar−1. These excellent As(V) rejection and high water permeability were attributed to the highly negatively charged surface of the SPEEK membrane, which could enhance the As(V) rejection through the Donnan exclusion mechanism or electrostatic repulsion between the negatively charged arsenate species and the negatively charged SPEEK membrane surface. A preliminary techno-economic assessment of a 1000 m3 h−1 plant suggests that using the proposed SPEEK hollow fiber membrane, the treatment cost was 0.15 US$ per m3, which thus could be economically viable for arsenic removal applications in China.

Stability of supported liquid membrane (SLM) has been a key issue in the application of high efficiency liquid membranes. In this paper, a nanoporous ion exchange membrane, prepared by blending polyethersulfone (PES) with sulfonated poly (phenyl ether ketone, SPPESK), was utilized as the stabilizing barrier for the extraction of lithium ion based on liquid–liquid membrane extraction. The membrane was prepared via immersion precipitation and the ratio between PES and SPPESK was varied in order to obtain a membrane with the best performance. It was found that at a PES/SPPESK ratio of 6/4 and a polymer concentration of 30 wt%, the membrane showed a Li + flux of 1.67×10 −8 mol cm −2 s −1 at a Li + feed concentration of 0.13 mol/L. The membrane demonstrated nearly unchanged stress but a slight decline in elongation after 50 days in contact with the organic extractant, indicating the potential solvent resistance. Using tributylphosphate (TBP) as the extractant and kerosene as the diluent, lithium extraction and stripping were demonstrated in both single-staged and sandwiched membrane extraction contactor systems. The preliminary results on using SPPESK/PES barrier membrane for stabilizing the liquid membrane will lead to a new scientific and technology development in lithium mining from brine and seawater in the near future.