Evolution of Business Intelligence: An Analysis from the Perspective of Social Network

Based on CiteSpace, Pajek and other software, this paper makes a visual analysis of the knowledge graph of the related literature of Business Intelligence and explores the future development trend of business intelligence. Taking the core periodicals of CNKI as the data source, key words are drawn and analyzed with the help of software. The total number of articles was 2938 from 2006 to 2020, and the number of articles published in the past 15 years was gradually levelled off. Among the 607 researchers, Yang Bingru is the representative; there are 424 journals, Journal of Information is the first, and 787 keywords are the most frequently used data mining. Our country still needs in-depth research in the field of business intelligence. Through the atlas, it directly shows that big data and machine learning are the frontier hot spots of future development, which provides research direction for researchers

Donnan Dialysis Desalination with a Thermally Recoverable Solute

This study presents a novel desalination technology that couples Donnan dialysis (DD) with thermally-recoverable solutes and utilizes low-grade heat as energy input. In the proposed process, saline feed streams and receiver solutions of concentrated NH4HCO3(aq) flow stepwise across cation- and anion-exchange membranes. The large transmembrane concentration differences of NH4+ and HCO3– set up electrochemical potential gradients to drive the uphill transport of Na+ and Cl– ions, respectively, from the saline feed into the receiver stream. Warming the two outlet streams using low-temperature thermal sources volatilizes NH3 and CO2, thus removing NH4HCO3 to yield desalinated product water and concentrated brine. The separated NH3(g) and CO2(g) are then recycled to reconstitute the receiver solution. The concept was first experimentally validated by desalinating brackish water simulated with 100 mM NaCl solutions to freshwater salinities (<17 mM). DD desalination was then demonstrated for larger ranges of feed and receiver concentrations of 100–1000 mM, and the experimental salt removals showed good agreement with theoretical Donnan equilibria (within 5%). The experimental results revealed that the unavoidable permeation of receiver solute co-ions due to imperfect membrane permselectivities is the main factor that prevents the theoretical thermodynamic potential from being reached. Nonetheless, current commercial ion-exchange membranes are sufficient to suppress the undesired co-ion leakage, yielding salt removals adequate for practical desalination. Module-scale analysis quantitatively showed that countercurrent DD operation can obtain higher desalination performance compared to co-current flows, achieving salt removals and water recovery yields as high as 95.5 and 87.5%, respectively. The utilization of low-grade thermal sources, such as waste heat and low-temperature geothermal reservoirs, as the primary energy input to drive the innovative approach opens up opportunities to lower the carbon intensity of desalination

Elucidating conductivity-permselectivity tradeoffs in electrodialysis and reverse electrodialysis by structure-property analysis of ion-exchange membranes

Ion-exchange membranes (IEMs) are used in environmental and energy technologies of electrodialysis (ED) desalination and reverse electrodialysis (RED) power generation, respectively. Recent studies reported empirical evidence that the conductivity and permselectivity of IEMs are bound by a tradeoff relationship, where an increase in ionic conductivity is accompanied by a decrease in counterion selectivity over co-ion. A fundamental understanding of this conductivity-permselectivity tradeoff is principal to inform membrane development. This study presents an IEM transport model to analytically relate conductivity and permselectivity to intrinsic membrane chemical and structural properties. The model employs the Nernst-Planck transport framework and incorporates counterion condensation theory to simulate the performance of IEMs in a range of ED and RED operations. The analysis revealed the mechanism for the tradeoff induced by bulk solution concentration: a higher salinity suppresses IEM charge-exclusion, thus lowering permselectivity, but elevates mobile ion concentration within the membrane matrix to improve conductivity. As such, IEM applications are practically confined to sub-seawater salinities, i.e., RED using hypersaline streams will not be efficient. In another tradeoff driven by IEM water sorption, increasing membrane swelling enhances effective ion diffusivity to raise conductivity, but diminishes permselectivity due to dilution of fixed charges. The transport model indicates that increasing membrane ion-exchange capacity and reducing thickness can yield highly selective and conductive IEMs

Influence of electrolyte on concentration-induced conductivity-permselectivity tradeoff of ion-exchange membranes

In ion-exchange membranes (IEMs), the concentration-induced tradeoff between conductivity and permselectivity constrains process performance. This study investigates the impacts of different electrolytes on the conductivity-permselectivity tradeoff of commercial cation and anion exchange membranes. Nine different electrolyte solutions containing mono-, di-, and trivalent ions, and spanning 1.5 orders of magnitude in concentration were examined. Effective conductivity is found to be determined by valency and mobility of the counterion and is insensitive to the co-ion identity. Apparent permselectivity declines with higher valency of the counterion and with lower valency of the co-ion. Overall, the IEMs exhibited different conductivity-permselectivity tradeoff behaviors across the electrolyte solutions investigated. The disparate tradeoff trends are shown to be governed by counter- and co-ion valencies, and counterion diffusivity. The study sheds light on the principal factors underpinning the tradeoff and advances the understanding of attainable conductivity-permselectivity performance in more complex water chemistries that are pertinent for practical IEM applications

Mobility of Condensed Counterions in Ion-Exchange Membranes: Application of Screening Length Scaling Relationship in Highly Charged Environments

Ion-exchange membranes (IEMs) are widely used in water, energy, and environmental applications, but transport models to accurately simulate ion permeation are currently lacking. This study presents a theoretical framework to predict ionic conductivity of IEMs by introducing an analytical model for condensed counterion mobility to the Donnan-Manning model. Modeling of condensed counterion mobility is enabled by the novel utilization of a scaling relationship to describe screening lengths in the densely charged IEM matrices, which overcame the obstacle of traditional electrolyte chemistry theories breaking down at very high ionic strength environments. Ionic conductivities of commercial IEMs were experimentally characterized in different electrolyte solutions containing a range of mono-, di-, and trivalent counterions. Because the current Donnan-Manning model neglects the mobility of condensed counterions, it is inadequate for modeling ion transport and significantly underestimated membrane conductivities (by up to ≈5× difference between observed and modeled values). Using the new model to account for condensed counterion mobilities substantially improved the accuracy of predicting IEM conductivities in monovalent counterions (to as small as within 7% of experimental values), without any adjustable parameters. Further adjusting the power law exponent of the screen length scaling relationship yielded reasonable precision for membrane conductivities in multivalent counterions. Analysis reveals that counterions are significantly more mobile in the condensed phase than in the uncondensed phase because electrostatic interactions accelerate condensed counterions but retard uncondensed counterions. Condensed counterions still have lower mobilities than ions in bulk solutions due to impedance from spatial effects. The transport framework presented here can model ion migration a priori with adequate accuracy. The findings provide insights into the underlying phenomena governing ion transport in IEMs to facilitate the rational development of more selective membranes. Keywords: Charge transport, Counterions, Electrical conductivity, Ions, Membrane

Advancing the conductivity-permselectivity tradeoff of electrodialysis ion-exchange membranes with sulfonated CNT nanocomposites

Ion exchange membranes, IEMs, are widely applied in water and energy technologies, such as, electrodialysis for desalination and reverse electrodialysis for sustainable power generation. However, a tradeoff between conductivity and permselectivity constrains the efficiency of IEM-based technologies. The incorporation of rationally functionalized 1-dimensional nanomaterials as fillers into the polymer matrix offers opportunities to depart from this tradeoff. In this study, we develop nanocomposite cation exchange membranes by incorporating sulfonic acid-functionalized carbon nanotubes, sCNTs, in sulfonated poly(2,6-dimethyl-1,4-phenyleneoxide) polymer matrix. The fabricated nanocomposite IEMs exhibit improved conductivity while maintaining permselectivity. Intrinsic resistivity, the reciprocal of conductivity, is lowered with greater blending of sCNTs fillers, decreasing by approximately 25% with 20 w/w% incorporation of sCNTs, while permselectivity is effectively unchanged across the different degrees of sCNT incorporation (within 2% variation). Compared with pristine membranes, the conductivity-permselectivity tradeoff line of the fabricated nanocomposite membranes is advantageously advanced, thus improving overall performance. Further characterization and analysis show a percolating network of carbon nanotubes is achieved in the polymer matrix with 10 w/w% sCNTs. We posit that the improved effective ionic conductivity is attributed to the interconnected sCNT network reducing the tortuosity of the ion transport path. This study demonstrates the promise of percolating 1D nanomaterial networks to potentially advance the conductivity-permselectivity tradeoff governing conventional IEMs

Advancing ion-exchange membranes to ion-selective membranes: principles, status, and opportunities

Ion-exchange membranes (IEMs) are utilized in numerous established, emergent, and emerging applications for water, energy, and the environment. This article reviews the five different types of IEM selectivity, namely charge, valence, specific ion, ion/solvent, and ion/uncharged solute selectivities. Technological pathways to advance the selectivities through the sorption and migration mechanisms of transport in IEM are critically analyzed. Because of the underlying principles governing transport, efforts to enhance selectivity by tuning the membrane structural and chemical properties are almost always accompanied by a concomitant decline in permeability of the desired ion. Suppressing the undesired crossover of solvent and neutral species is crucial to realize the practical implementation of several technologies, including bioelectrochemical systems, hypersaline electrodialysis desalination, fuel cells, and redox flow batteries, but the ion/solvent and ion/uncharged solute selectivities are relatively understudied, compared to the ion/ion selectivities. Deepening fundamental understanding of the transport phenomena, specifically the factors underpinning structure-property-performance relationships, will be vital to guide the informed development of more selective IEMs. Innovations in material and membrane design offer opportunities to utilize ion discrimination mechanisms that are radically different from conventional IEMs and potentially depart from the putative permeability-selectivity tradeoff. Advancements in IEM selectivity can contribute to meeting the aqueous separation needs of water, energy, and environmental challenges

Donnan dialysis for phosphate recovery from diverted urine

There is a critical need to shift from existing linear phosphorous management practices to a more sustainable circular P economy. Closing the nutrient loop can reduce our reliance on phosphate mining, which has well-documented environmental impacts, while simultaneously alleviating P pollution of aquatic environments from wastewater discharges that are not completely treated. The high orthophosphate, HxPO4(3-x)-, content in source-separated urine offers propitious opportunities for P recovery. This study examines the use of Donnan dialysis (DD), an ion-exchange membrane-based process, for the recovery of orthophosphates from fresh and hydrolyzed urine matrixes. HxPO4(3-x)- transport against an orthophosphate concentration gradient was demonstrated and orthophosphate recovery yields up to 93% were achieved. By adopting higher feed to receiver volume ratios, DD enriched orthophosphate in the product stream as high as ≈2.5 × the initial urine feed concentration. However, flux, selectivity, and yield of orthophosphate recovery were detrimentally impacted by the presence of SO42− and Cl− in fresh urine, and the large amount of HCO3− rendered hydrolyzed urine practically unsuitable for P recovery using DD. The detrimental effects of sulfate ions can be mitigated by utilizing a monovalent ion permselective membrane, improving selectivity for HxPO4(3-x)- transport over SO42− by 3.1 × relative to DD with a conventional membrane; but the enhancement was at the expense of reduced orthophosphate flux. Critically, widely available and low-cost/waste resources with sufficiently high Cl− content, such as seawater and waste water softening regenerant rinse, can be employed to improve the economic viability of orthophosphate recovery. This study shows the promising potential of DD for P recovery and enrichment from source-separated urine

Phase equilibria insights into amine-water-NaCl interactions in liquid-liquid biphasic systems for temperature swing solvent extraction desalination

This study sheds light on the fundamental phenomena governing temperature swing solvent extraction (TSSE) desalination by investigating the influence of temperature on the equilibrium partitioning of water, salt, and solvent. The distribution of components across a range of temperatures and feed salinities typical to TSSE hypersaline desalination was examined for two amine solvents. A tradeoff between selectivity and productivity is established, providing a novel framework to assess TSSE performance. Salt was shown to be a key determinant in equilibrium partitioning by diminishing the ability of the solvent to extract water at lowered temperatures and salting-out amines from the aqueous phase. Na+ and Cl− ions consistently partition into the solvent phase in equimolar ratios. Analysis further reveals a linear correlation between the natural logarithms of salt activity coefficients and water contents of the organic phase. The two collaborating results suggest that water-ion interactions are more important than amine-ion interactions in the organic phase, resolving a critical gap in the understanding of salt transport. The findings of this study can provide important insights for the informed development of temperature swing solvent extraction for hypersaline desalination