Sequential Adsorption Process Research Articles

Construction of a Fluorinated-Anion Pillared Metal-Organic Framework Exhibiting Dual-Pore Architecture for Simultaneous Enhancement of C2H2 Adsorption Capacity and Selectivity.

Physisorption-based separation processes represents a promising alternative to the conventional thermally driven methods, such as cryogenic separation. However, a significant challenge lies in balancing the trade-off between adsorption capacity and selectivity of adsorbents. In this study, we introduce a novel fluorinated-anion pillared metal-organic frameworks (APMOFs) featuring a dual-pore architecture, constructed using a pyridine-oxazole bifunctional ligand. The inherent low symmetry of the ligand leads to significant distortion of the fluorinated-anion pillars, resulting in a distinctive type of APMOFs characterized by dual-pore architecture. On pore structure with constrict pore width is enriched with a high density of anion fluorinated pillars, offering numerous active sites advantageous for enhancing separation selectivity. Concurrently, the other pore structure exhibits larger dimensions, facilitating increased gas molecule accommodation and thereby augmenting adsorption capacity. Gas sorption studies reveal a substantial C2H2 adsorption capacity and a high C2H2/CO2 separation selectivity. Breakthrough experiments confirm its exceptional separation performance, while theoretical investigations elucidate a sequential adsorption process within these APMOFs, underscoring the efficacy of this strategy in overcoming trade-off limits in adsorbents.

Interfacial mechanics of β-casein and albumin mixed protein assemblies at liquid-liquid interfaces

Protein emulsifiers play an important role in formulation science, from food product development to emerging applications in biotechnologies. The impact of mixed protein assemblies on surface composition and interfacial shear mechanics remains broadly unexplored, in comparison to the impact that formulation has on dilatational mechanics and surface tension or pressure. In this report, we use interfacial shear rheology to quantify the evolution of interfacial shear moduli as a function of composition in bovine serum albumin (BSA)/β-casein mixed assemblies. We present the pronounced difference in mechanics of these two protein, at oil interfaces, and observe the dominance of β-casein in regulating interfacial shear mechanics. This observation correlates well with the strong asymmetry of adsorption of these two proteins, characterised by fluorescence microscopy. Using neutron reflectometry and fluorescence recovery after photobleaching, we examine the architecture of corresponding protein assemblies and their surface diffusion, providing evidence for distinct morphologies, but surprisingly comparable diffusion profiles. Finally, we explore the impact of crosslinking and sequential protein adsorption on the interfacial shear mechanics of corresponding assemblies. Overall, this work indicates that, despite comparable surface densities, BSA and β-casein assemblies at liquid–liquid interfaces display almost 2 orders of magnitude difference in interfacial shear storage modulus and markedly different viscoelastic profiles. In addition, co-adsorption and sequential adsorption processes are found to further modulate interfacial shear mechanics. Beyond formulation science, the understanding of complex mixed protein assemblies and mechanics may have implications for the stability of emulsions and may underpin changes in the mechanical strength of corresponding interfaces, for example in tissue culture or in physiological conditions.

Room temperature atomic layer deposition of zinc titanium oxide using sequential adsorption of dimethyl zinc and tetrakis(dimethylamino)titanium

Complex oxide films of TiO2 and ZnO are deposited by RT atomic layer deposition (ALD) with a sequential adsorption process. In this ALD, a Zn precursor of dimethyl zinc (DMZ) and a Ti precursor of tetrakis(dimethylamino)titanium (TDMAT) are used. In the sequential adsorption step, the DMZ saturation on the surface is followed by partial adsorption of TDMAT. It is assumed that the TDMAT molecule is adsorbed on the DMZ uncovered area. The mixed layer of DMZ and TDMAT is formed in the adsorption step, followed by being oxidized with the plasma-excited humidified Ar. All the ALD processes are performed at RT without any sample heating in the ALD chamber. The growth per cycle of the balanced Zn and Ti oxide deposition is recorded at 0.086 nm/cycle. The mixing ratio of Zn and Ti is controlled by the TDMAT exposure in the adsorption step. In this study, the reaction model and the related rate equations to calculate the mixing concentration ratio are proposed based on the in situ observation of the surface reaction by IR absorption spectroscopy.

Density and Correlation in a Random Sequential Adsorption Model

We consider the random sequential adsorption process on the one- dimensional lattice with nearest-neighbor exclusion. In this model, each site s 2 Z starts empty and a particle will be deposited in it at time ts, where (ts)s2Z is a sequence of independent random variables uniformly distributed on the interval [0; 1]. The site will be occupied if both of its neighbors are vacant. Analytical expressions for the density of occupied sites and the pair correlation function, for all time t, are well-established and have been obtained through methods such as generating functions and differential equations. In this study, we present a method based on probabilistic arguments for the calculation of these expressions.

Reclamation of real textile wastewater by sequential advanced oxidation and adsorption processes using corn-cob based materials

Wastewater management has become crucial for sustaining biological life in the near future. One of the key aspects is integration of treatment processes aiming reuse of treated water for many purposes instead of water discharge. This study focused on combining two different methods, photo-Fenton-like oxidation, and adsorption, for treatment of real textile wastewater to improve water quality to be reused for irrigation. The real textile wastewater was collected from a local plant and subjected to photo-Fenton-like oxidation and adsorption as hybrid process. The operational parameters were optimized for each step by assessing the water quality according to the domestic regulations for irrigation water. The photo-Fenton-like oxidation itself was not successful to achieve the targeted water quality for reuse whereas adsorption as an additional step made the treated water reusable in terms of organic content. But the treated water still contained a certain amount of salinity due to extreme salt usage in textile processing. It was concluded that the treated water at the end of hybrid process could be used for salinity resistant plants such as sugar beet, barley, and cotton which demonstrates a promising contribution to the circular economy for biomass.

Facile In-Situ photocatalytic reduction of AuNPs on multilayer Core-Shell Fe3O4@SiO2@PDA magnetic nanostructures and their SERS application

Surface-enhanced Raman scattering (SERS) is a promising analytical technique for the rapid, sensitive, and repeatable detection in various SERS application fields. Herein, a new type of potential magnetically recyclable SERS substrate was designed and rapidly synthesized via a facile three-step template method. First, the magnetic ferroferric oxide (Fe3O4) cores were prepared by a convenient solvothermal approach, and coated with a thin layer of silica by a sol–gel process in order to improve their stability in complicated environments. Next, the negatively charged polydopamine (PDA)/K6[SiW11VIVO40]·7H2O (PDA/SiW11V) outer shell was assembled upon the magnetic Fe3O4@SiO2 core–shell nanoparticles via a layer-by-layer sequential adsorption process using the stickiness of PDA. The SiW11V multilayer shell can be used as the subsequent photocatalytic reduction precursors for the in-situ loading of high-density gold nanoparticles (AuNPs), without any other organic additives. The AuNPs decorated multilayer core–shell Fe3O4@SiO2@PDA magnetic nanostructures were employed as a potential magnetically recyclable SERS substrate, and showed excellent SERS performance. Using crystal violet (CV) as a model target, the as-fabricated AuNPs modified multilayer core–shell Fe3O4@SiO2@PDA magnetic nanostructures SERS substrates exhibited significant enhancement, and pushed the detection limit down to 10-12 M. Aside from the ultrahigh sensitivity, these SERS substrates also possess an excellent reproducibility (relative standard deviation (RSD) ∼ 8.3%), long-term stability (75 days), and unique chemical stability capability in different organic solvents and different environments with pH ≤ 10. Furthermore, a real-life application is also performed by the detection of melamine in spiked milk solution using the as-prepared magnetic nanostructures SERS-active substrates (limit of detection (LOD), 10-8 M). These results highlight that the rational design and controllable synthesis of multifunctional magnetic SERS substrates is a promising strategy in many different application fields such as biosensing, photoelectrocatalysis, and medical diagnosis.

Random adsorption process of linear k-mers on square lattices under the Achlioptas process.

We study the explosive percolation with k-mer random sequential adsorption (RSA) process. We consider both the Achlioptas process (AP) and the inverse Achlioptas process (IAP), in which giant cluster formation is prohibited and accelerated, respectively. By employing finite-size scaling analysis, we confirm that the percolation transitions are continuous, and thus we calculate the percolation threshold and critical exponents. This allows us to determine the universality class of the k-mer explosive percolation transition. Interestingly, the numerical simulation suggests that the universality class of the explosive percolation transition with the AP alters when the k-mer size changes. In contrast, the universality class of the transition with the IAP is independent of k, but it differs from that of the RSA without the IAP.

A kinetic model for 2,4-dichlorophenol adsorption and hydrodechlorination over a palladized biofilm

Adsorption and catalytic hydrodechlorination (HDC) of aqueous 2,4-DCP by palladium nanoparticles (Pd0NPs) associated with a biofilm (i.e., a Pd0-biofilm) was investigated in terms of the removal efficiency of 2,4-DCP, dechlorinated product selectivity, and reduction kinetics. Experiments were executed with Pd0-biofilm and with abiotic Pd0NPs-film alone. The 2,4-DCP-adsorption capacity of Pd0-biofilm was 2- to 5-fold greater than that of abiotic Pd0NPs-film, and the adsorption accelerated dechlorination by Pd0-biofilm, including selectivity to phenol instead of mono-chlorophenols. A mechanistic kinetic model was developed to represent the sequential adsorption and reduction processes. Modeling results represented well the removal of 2,4-DCP and quantified that Pd0-biofilm had a strong affinity for adsorbing 2,4-DCP. The strong adsorption increased the volume-averaged concentration of 2,4-DCP concentration inside the Pd0-biofilm, compared to the concentration in the bulk liquid. This increase in the local concentration of 2,4-DCP led to a 2- to 4-fold increase in the reduction rate of 2,4-DCP in Pd0-biofilm, compared to abiotic Pd0NPs-film. Thus, coupling Pd0NPs with the biofilm promoted 2,4-DCP removal and full dechlorination despite its low concentration in bulk water.

Multilayer Random Sequential Adsorption

In this work, we present a variant of the multilayer random sequential adsorption (RSA) process that is inspired by orthogonal resource sharing in wireless communication networks. In the one-dimensional (1D) version of this variant, the deposition of overlapping rods is allowed only if they are assigned two different colors, where colors are symbolic of orthogonal resources, such as frequency bands, in communication networks. Owing to a strong spatial coupling among the deposited rods of different colors, finding an exact solution for the density of deposited rods of a given color as a function of time seems intractable. Hence, we propose two useful approximations to obtain the time-varying density of rods of a given color. The first approximation is based on the recursive use of the known monolayer RSA result for the indirect estimation of the density of rods for the multilayer version. The second approximation, which is more accurate but computationally intensive, involves accurate characterization of the time evolution of the gap density function. This gap density function is subsequently used to estimate the density of rods of a given color. We also consider the two-dimensional (2D) version of this problem, where we estimate the time-varying density of deposited circles of a given color as a function of time by extending the first approximation approach developed for the 1D case. The accuracy of all the results is validated through extensive Monte Carlo simulations.

Electroporation-coupled electrochemical oxidation for rapid and efficient water disinfection with Co3O4 nanowire arrays-modified graphite felt electrodes

Biologically unsafe drinking water occurs in developing regions lack of centralized water treatment plants. Herein, Co3O4 nanowire electrodes with Co3O4 nanowire arrays grown on graphite felt were fabricated and employed to construct a flow-through electrode system (FES) for rapid and efficient water disinfection, which achieved over 6.7-log E. coli removal under applied voltage of 2.5 V and flow rate of 65 mL/min (HRT ∼ 4.5 s) with energy consumption of 2.3 Wh/m3. The FES also achieved over 6.7-log removal at 2.5 V for the Gram-negative P. aeruginosa under ∼ 60 mL/min and for Gram-positive bacteria (E. faecalis and S. aureus) under ∼ 40 mL/min, and the Gram-negative bacteria were more vulnerable to FES disinfection than Gram-positive ones due to their larger sizes and thinner cell walls. In-situ sampling and live/dead backlight staining experiments revealed that pathogen inactivation mainly occurred on anode via the sequential adsorption, inactivation and desorption processes under the mass transfer forces of electric field attraction and flow scouring effect in porous electrodes. The disinfection mechanisms on the Co3O4 nanowire anode were recognized to be electroporation and electrochemical oxidation, and the pores generated by electroporation can provide diffusion channels for reactive species into the pathogen cells, promoting the disinfection performance.

Jamming densities of random sequential adsorption on d-dimensional cubic lattices.

The rate of convergence of the jamming densities to their asymptotic high-dimensional tree approximation is studied, for two types of random sequential adsorption (RSA) processes on a d-dimensional cubic lattice. The first RSA process has an exclusion shell around a particle of nearest neighbors in all d dimensions (N1 model). In the second process the exclusion shell consists of a d-dimensional hypercube with length k=2 around a particle (N2 model). For the N1 model the deviation of the jamming density ρ_{r}(d) from its asymptotic high d value ρ_{asy}(d)=ln(1+2d)/2d vanishes as [ln(1+2d)/2d]^{3.41}. In addition, it has been shown that the coefficients a_{n}(d) of the short-time expansion of the occupation density of this model (at least up to n=6) are given for all d by a finite correction sum of order (n-2) in 1/d to their asymptotic high d limit. The convergence rate of the jamming densities of the N2 model to their high d limits ρ_{asy}(d)=dln3/3^{d} is slow. For 2≤d≤4 the generalized Palasti approximation provides by far a better approximation. For higher d values the jamming densities converge monotonically to the above asymptotic limits, and their decay with d is clearly faster than the decay as (0.432332...)^{d} predicted by the generalized Palasti approximation.

Modeling Rydberg gases using random sequential adsorption on random graphs

The statistics of strongly interacting, ultracold Rydberg gases are governed by the interplay of two factors: geometrical restrictions induced by blockade effects, and quantum mechanical effects. To shed light on their relative roles in the statistics of Rydberg gases, we compare three models in this paper: a quantum mechanical model describing the excitation dynamics within a Rydberg gas, a Random Sequential Adsorption (RSA) process on a Random Geometric Graph (RGG), and a RSA process on a Decomposed Random Intersection Graph (DRIG). The latter model is new, and refers to choosing a particular subgraph of a mixture of two other random graphs. Contrary to the former two models, it lends itself for a rigorous mathematical analysis; and it is built specifically to have particular structural properties of a RGG. We establish for it a fluid limit describing the time-evolution of number of Rydberg atoms, and show numerically that the expression remains accurate across a wider range of particle densities than an earlier approach based on an RSA process on an Erdos-Renyi Random Graph (ERRG). Finally, we also come up with a new heuristic using random graphs that gives a recursion to describe a normalized pair-correlation function of a Rydberg gas. Our results suggest that even without dissipation, on long time scales the statistics are affected most by the geometrical restrictions induced by blockade effects, while on short time scales the statistics are affected most by quantum mechanical effects.

Thermal stability evaluation of selected zeolites for sustainable thermochemical energy storage

ABSTRACT In recent times, the thermochemical energy storage (TCES) method is gaining prominence due to its high energy storage density and minimal heat losses compared to the conventional thermal energy storage (TES) methods. This paper presents the cyclability behavior of selected zeolites for the TCES applications. The zeolites were subjected to sequential desorption and adsorption processes for five times using a differential thermogravimetric analyzer (DTG-60H). To investigate their suitability for the commonly available sources of thermal energy (e.g. solar energy, industrial waste heat), the samples were heated up to 150°C. These zeolites were also tested on Brunauer–Emmet–Teller (BET) analyzer for total surface areas and pore volumes, thus to read their sorption behavior. A field emission scanning electron microscope (FESEM) equipped with an energy dispersive X-ray (EDX) analyzer was used to examine the surface morphology and elemental composition of zeolite sorbents before and after the multi-cycle test run. The changes in the mass of a material during a process, either desorption or adsorption, were notably almost the same across the cycles tested, which confirms the cyclability of the materials tested. Amongst the tested materials, Zeolite-NaY and Zeolite-HY exhibited relatively better process enthalpies owing to their active water adsorption capacities. Of the six materials tested, Zeolite-NaY has offered better results and its enthalpies range from 287.5 J g−1 to 348.5 J g−1 for the desorption and from 81 J g−1 to 292.1 J g−1 for the adsorption. A mass gain was noticed for each of the tested materials as they undergo the cooling process, thus affecting water vapor adsorption capacity negatively.

Efficient treatment for textile wastewater through sequential photo Fenton-like oxidation and adsorption processes for reuse in irrigation

The present study investigates the treatment for textile wastewater through sequential photo Fenton-like oxidation and adsorption processes for reuse in irrigation. The optimum conditions were investigated to reach the minimum irrigation standarts in Turkey. Assessment of the treated wastewater as an irrigation water, evaluation of the agricultural waste as an adsorbent and support material for catalyst are the main significances of this study. Walnut shell and rice husk based adsorbents and catalysts which contain 10% by weight of active site BiBO3 (B:Fe,Ni) were prepared and used. At the optimum conditions of the photo Fenton-like oxidation; the highest total organic carbon removal, TOC, (20–30%) was achieved with the iron containing walnut shell based catalysts. Adsorption studies were carried out as a consequent step with walnut shell based activated carbon. At the end of adsorption step, approximately 86% TOC and 58% Chemical Oxygen Demand (COD) removals were observed. Irrigation water standards were provided for TOC, color, turbidity, total suspended solids, and pH after the adsorption step. Temkin and Dubinin–Radushkevich isotherm models were found to best fit to the adsorption data. The adsorption rate followed second order kinetic model. As a result, the treated wastewater using photo-Fenton-like oxidation and adsorption process met the quality of irrigation standarts regarding TOC, color, turbidity and TSS. Also irrigation standarts were obtained considering sodium adsorption ratio (SAR). Treated wastewater have been found to be used in cultivation of plants such as barley, cotton, sugar beet, grass, spinach, long wheat grass, date palm tree, asparagus, bermuda grass sorghum. The application of the hybrid process showed that the proposed method can be implemented effectively for the treatment of real textile wastewater.

Nonlinear dynamical modeling of adsorption and desorption processes with power-law kinetics: Application to CO_{2} capture.

Modeling of random sequential adsorption (RSA) process is studied in this paper as this kind of process is close to the surface adsorption phenomenon that is, for instance, exploited in gas sensors or for liquid or gas purification. Analysis and simulation of the RSA process is first performed to highlight a power-law kinetic behavior. Such behaviors are often modeled in the literature with fractional models. The paper, however, shows that fractional models are not able to capture some important properties of the RSA process. A nonlinear model and the associated parameters tuning method are, thus, proposed. A discussion on the ability of the proposed model to capture the power-law kinetics without exhibiting some of the drawbacks of fractional models is proposed. This nonlinear model is then modified to take into account the reverse desorption process. The proposed modeling approach is applied to experimental data of CO_{2} capture.

Automotive Wash Effluent Treatment Using Combined Process of Coagulation/Flocculation/Sedimentation–Adsorption

In the treatment of wastewater from vehicle washing, the coagulation/flocculation process using inorganic coagulant is mostly applied; it may or may not be combined with other processes. In literature, few studies use natural coagulants and assess the surfactants’ removal among the physical-chemical parameters, particularly using the adsorption process. In order to fill this knowledge gap, this work aimed to treat the car wash wastewater, applying a combined process of coagulation/flocculation/sedimentation (C/F/S) and adsorption. Process efficiency was evaluated according to the removal of color, turbidity, total solids, volatile solids, total dissolved solids, chemical oxygen demand and surfactants. For primary effluent treatment, C/F/S experiments were performed with Tanfloc SG to investigate the influence of the natural coagulant concentration in color and turbidity removal efficiency. The results showed that 220 mg L−1 was the best coagulant concentration (turbidity = 97.5%; color = 92.5%) (p < 0.05). The supernatant of the C/F/S process was applied to the sequential adsorption process (kinetics and isotherm) with mineral activated carbon. The equilibrium time of the kinetic experiment was established after 2 h of contact, and the Langmuir isotherm model best described the surfactant adsorption behavior (R2 = 0.93; qmax = 5.65 mg g−1). The combined process enhanced the treatment efficiency achieving an overall removal efficiency of 97.3% for color, 98.8% for turbidity, 92.6% for chemical oxygen demand, and 97.2% for surfactants. The combined process proved to be promising for the treatment of car wash wastewater, presenting a reduction surfactant concentration and on the other parameters evaluated, contributing to environmental sustainability.

Efficient treatment for textile wastewater through sequential electrocoagulation, electrochemical oxidation and adsorption processes: Optimization and toxicity assessment

In this work, the sequential Electrocoagulation + Electro-oxidation + Activated carbon adsorption (EC + EO + AC) process was studied as an alternative for the treatment of an industrial textile wastewater (TWW) issuing from a manufacturing company located in Medellín (Colombia). The EC's and EO's operational conditions were optimized using a Box-Behnken experimental design, the Response Surface Methodology and a constrained nonlinear optimization algorithm in terms of organic matter degradation efficiency. The best performance for EC (i. e., dye removal = 94%, COD and TOC degradation of 45 and 40%, respectively) was obtained using Fe anode and Boron Doped Diamond (BDD) cathode, with current density, j EC , equals to 5 mA/cm 2 , pH = 9.3, 60 RPM and 10 min of electrolysis. After EC treatment, the effluent biodegradability (evaluated as the BOD 5 /COD ratio) increases from 0.14 to 0.23. Regrettably, EC was not effective for the removal of acute toxicity to Artemia salina since the treated effluent remained very toxic (100%). The treatment of EC's effluent by EO enhanced organic pollutant removal. For EC + EO sequential process, EO optimal operational conditions ( j EO = 10 mA/cm 2 , pH = 3, 240 RPM , BDD as anode and Fe as cathode) allowed reduction of 100% of color, 88% of COD and 79% of TOC after 30 min of electrolysis. Moreover, the BOD 5 /COD ratio increased from 0.23 to 0.58; however, the treated effluent remained very toxic to the Artemia salina . Consequently, an activated carbon adsorption step was included to complete the treatment process. Thus, by coupling the EC + EO + AC process, effluent's acute toxicity decreased completely. From molecular weight distribution analysis, it was concluded that EC + EO was efficient in eliminating low molecular weight (< 5 kDa) compounds. Finally, the operation cost, which includes chemical reagents, electrodes, energy consumption, and sludge disposal, for the EC + EO + AC sequential process was estimated in 3.83 USD /m 3 . Graphical abstract

Assessment of the optimized treatment of indigo-polluted industrial textile wastewater by a sequential electrocoagulation-activated carbon adsorption process

Wastewater collected from a local jean manufacturing plant was treated using an electrocoagulation process (EC) coupled with activated carbon (AC) adsorption. The process variables were optimized using multivariate regression coupled with nonlinear programming with nonlinear restrictions to achieve the lowest possible cost while keeping a high enough degradation rate for chemical oxygen demand (COD), color, and turbidity to fulfill the Colombian environmental regulation requirements. Under optimal conditions (pH = 5.4, σ =2 mS/cm, j =14 mA/cm2, and t = 11 min) color, COD, and TOC removals of 95%, 63%, and 51%, respectively, were achieved. The biodegradability index also increased from 0.13 to 0.29, whereas toxicity tests showed a remaining toxicity of 45%. A kinetic study was conducted for the EC process. The activated carbon (AC) adsorption process was successfully used to completely remove toxicity, while further increasing color, COD, and TOC removals to 96%, 72%, and 61%, respectively. The conditions for the AC adsorption process (20 g/L of AC and 1 h) were determined by experimental adsorption isotherms and kinetic studies. The optimized EC/AC process led to an effluent satisfying the Colombian regulations and seems technologically viable with lower costs than other similar process that were reported in previous works.

Comparison of carbonized and graphitized carbon fiber electrodes under flow-through electrode system (FES) for high-efficiency bacterial inactivation

The disinfection performance of a flow-through electrode system (FES) was systematically evaluated using different carbonized (C1, C2, and C3) and corresponding graphitized (G1, G2, and G3) carbon fiber felt (CFF) electrodes. The physicochemical and electrochemical properties were characterized to identify the differences among CFFs. Graphitized CFFs (gCFFs) can achieve complete inactivation of Escherichia coli (>6 log) at the voltage of 3 V and flux of 120–3600 L/(m2 h) for high conductivity and chemical stability, while carbonized CFFs (cCFFs) only achieved around 1 log removal with obvious carbon corrosion. For the gCFFs, G1 (>6 log removal) with higher conductivity, better graphite structure, and larger surface area (related to fiber diameter and density) presented better disinfection performance at the flow rate of 30 mL/min than G2 (∼3 log) and G3(∼1 log). Furthermore, no regrowth and reactivation of bacteria occurred during the storage under visible light illumination after FES treatment. Three parallel FESs with G1 were operated continuously for one week (24 h per day, 7 days) treating the solution with an E. coli concentration ranging from 106 to 107 CFU/mL at the applied voltage of 3 V and the flow rate of 20 mL/min. No live bacteria were detected in the effluent of any of these three FESs. In-situ sampling experiments demonstrated that the inactivation of bacteria on anode was the dominant mechanism for FES treatment, which can be attributed to the sequential adsorption, direct-oxidation and desorption process on anode, instead of indirect oxidation by generating chemical oxidants. In addition, hydroxide ion generated from cathode reaction enhanced anode adsorption and inactivation of bacteria by providing alkaline environment. Combining the analysis results of material properties and disinfection performance, the gCFF-based FES was suggested to be a low-cost, high-efficiency, and safe alternative for future water disinfection.

A novel FastRSA algorithm: Statistical properties and evolution of microstructure

While the Random Sequential Adsorption (RSA) process for the generation of 2D geometries containing discrete entities has been extensively studied, both in terms of numerical simulations and in terms of its statistical properties, all the mechanisms involved are not fully understood, especially in dense configurations of elongated particles. This is mainly due to the very slow asymptotic approach to high packing configurations, especially when highly elongated particles are involved, which makes the creation of such configurations a time consuming task. For the estimation of the statistical properties of such configurations we therefore have to resort to extrapolations that do not always give accurate results. In this work we reveal the interaction of the mechanisms that come into play in the RSA process. We specifically show that the overall result of an RSA process is the summary outcome of these interwoven mechanisms, namely those involving the formation and destruction of Particle Area, Overlap Area and Influence Area – terms which we introduce and define in this work – resulting in a behavior that often appears counter-intuitive. We also show the shift of their importance as the particle aspect ratio α varies and explain how nematic structures are created when high aspect ratio particles are involved as well as the mechanisms behind their appearance. Following this, we propose a new algorithm for the process of random sequential adsorption (named FastRSA) which is capable of creating very high count configurations through all the range of particle aspect ratios and which follows Feder’s law with a θ∼τ−1∕2 behavior instead of the θ∼τ−1∕3 of the classic approach, where τ is the number of attempts to place a particle and θ is the degree of packing. We show how the new algorithm can be coupled with the classic RSA approach and point out the benefits of such a coupling. Use of the FastRSA algorithm has enabled us to study the evolution of the extent of packing using actual geometries, without the need to resolve to extrapolations and assumptions. For the case of highly elongated particles, this is the first time in our knowledge that estimations of maximum packing from actual configurations near the jamming limit have been obtained.