Boosting optical nonlinearity in epsilon-near-zero trilayer coatings.

Materials with large optical nonlinearity are highly desired for various applications such as all-optical signal processing and storage. Recently, indium tin oxide (ITO) has been found to possess strong optical nonlinearity in the spectral region where its permittivity vanishes. Here, we demonstrate that ITO/Ag/ITO trilayer coatings, deposited by magnetron sputtering with high-temperature heat treatment, can significantly enhance the nonlinear response in their effective epsilon-near-zero (ENZ) regions. The obtained results show that the carrier concentrations of our trilayer samples can reach 7.25 × 1021 cm-3, and the ENZ region can shift to the spectrum close to the visible range. In the ENZ spectral region, the ITO/Ag/ITO samples exhibit enhanced nonlinear refractive indices as large as 2.397 × 10-15 m2 W-1, over 27 times larger than that of an individual ITO layer. Such a nonlinear optical response is well described using a two-temperature model. Our findings provide a new paradigm for developing nonlinear optical devices for applications requiring low power.

Dissipation rates, residue distribution, degradation products, and degradation pathway of sulfoxaflor in broccoli.

Broccoli was selected as the research object in this paper to reveal the dissipation, distribution, and degradation pathway of sulfoxaflor under greenhouse and open-field cultivation conditions for the ecological risk assessment of sulfoxaflor. Results showed that the dissipation of sulfoxaflor in broccoli leaves, flowers, stems, roots, and the whole broccoli was in accordance with the first-order kinetic equation. The sulfoxaflor concentration in broccoli roots reached the maximum value after 1 day of application and then gradually decreased. The degradation half-lives of sulfoxaflor in the roots, leaves, flowers, stems, and whole broccoli were between 2.3 and 19.8 days. The longest degradation half-life of sulfoxaflor was in Heilongjiang under greenhouse cultivation. The terminal residue of sulfoxaflor in broccoli was in the range of 0.005-0.029 mg/kg, and the proportion of sulfoxaflor residue in broccoli leaves was the largest. Thirteen transformation products were separated and identified by ultrahigh-performance liquid chromatography-quadrupole time-of-flight mass spectrometry, and their kinetic evolution was studied. The cleavage of the N = S bond, C-S bond, C-O bond, and cyanide, as well as glucosylation, hydroxylation, SO extrusion, elimination, sulfhydrylation, ketonization, defluorination, and rearrangement, was inferred as the mechanism. Overall, these results can provide guidance for the supervision of the safe application of sulfoxaflor.

Visible to near-infrared nearly perfect absorption from alternate silica and chromium layers deposited by magnetron sputtering.

We present a novel, to the best of our knowledge, broadband and angle-insensitive nearly perfect absorber design composed of alternate silica and chromium layers. We show that by depositing a chromium nanofilm on a chromium substrate with a silica spacer, the absorption will significantly enhance from the visible to near-infrared. Then, another silica film is placed on the top of the layered structure as an antireflection coating, resulting in the broadband near-perfect absorption. We fabricate the proposed absorber by magnetron sputtering. The measured results show that our device has an average absorption over 97% in a wide range of wavelengths ranging from 350 to 1170 nm, and its absorption performance exhibits a good angular tolerance up to 50°. The presented absorber design offers a good prospect for large-scale and low-cost manufacturing of absorption-based optoelectronic devices.

Dissipation and dietary risk assessment of kasugamycin and saisentong in Chinese cabbage.

A quick, easy, cheap, effective, rugged, and safe pretreatment method using dispersive solid-phase extraction was developed to quantify kasugamycin in Chinese cabbage samples by using ultra-performance liquid chromatography/tandem mass spectrometry. A pretreatment method involving precolumn transformation was utilized to determine the residue of saisentong in Chinese cabbage through high-performance liquid chromatography/ultraviolet detection. These methods were successfully applied through field trials to determine the contents of kasugamycin and saisentong in Chinese cabbage. The dissipation of kasugamycin and saisentong in Chinese cabbage followed first-order kinetics with a linear correlation coefficient of 0.9066-0.9731 at the 95% confidence level. The half-lives of kasugamycin and saisentong in Chinese cabbage were 1.8-2.0 and 2.2-3.8 days, respectively. Terminal residual levels of kasugamycin in Chinese cabbage were not detected 14 days after application. The dietary risk assessment of kasugamycin and saisentong in Chinese cabbage showed that their risk quotients were 0.93 and 2.58%, respectively, in the preharvest interval (PHI) of 14 days. Kasugamycin and saisentong in Chinese cabbage did not pose potential health hazards at PHI of 14 days. The maximum residue limits of kasugamycin and saisentong in Chinese cabbage were 0.02 and 0.36 mg/kg, respectively, and 14 days was the safe PHI.

Effects of fertilization on the triafamone photodegradation in aqueous solution: Kinetic, identification of photoproducts and degradation pathway.

Triafamone is a highly effective, low toxicity sulfonamide herbicide widely used for weeding paddy fields. The triafamone photodegradation in water environment must be explored for its ecological risk assessment. In this work, the effects of chemical fertilizer (urea, diammonium phosphate, potassium chloride, and potassium sulfate), urea metabolites (CO32- and HCO3-), and organic fertilizers (unfermented organic fertilizer [UOF] and fermented organic fertilizer [FOF]) on the triafamone photodegradation in aqueous solution under simulated sunlight were evaluated. Results showed that the triafamone photodegradation rate was unaffected by urea. The half-life of triafamone decreased from 106.8 h to 68.4 h with increasing diammonium phosphate concentration. Potassium chloride, potassium sulfate, CO32-, and HCO3- could accelerate the triafamone photodegradation at all concentrations, whereas the degradation rate of triafamone decreased when the concentration of potassium sulfate or CO32- was 2000 mg/L. Triafamone photodegradation was promoted by 20-200 mg/L UOF and FOF but decreased to 236.6 and 142.3 h when the concentration reached 2000 mg/L. Twenty-three transformation products were isolated and identified from triafamone by using ultra-performance liquid chromatography with quadrupole time-of-flight mass spectrometry under simulated sunlight irradiation, and the kinetic evolution of these products was explored. Five possible degradation pathways were inferred, including the cleavage of C-N, C-C, and C-O bonds; CO bond hydrogenation; the cleavage of triazine ring; the cleavage of the sulfonamide bridge; hydroxylation; hydroxyl substitution; methylation; demethylation; amination; and rearrangement. In summary, these results are important for elucidating the environmental fate of triafamone in aquatic systems and further assessing environmental risks.

Identification and Characterization of Herbicide Penoxsulam Transformation Products in Aqueous Media by UPLC-QTOF-MS.

Photodegradation is an important non-biodegradation process of pesticide degradation in aquatic environments. In this study, the effect of different forms of nitrogen on the photodegradation kinetics of penoxsulam was investigated. The photodegradation of penoxsulam was accelerated by NO3- and NO2- but was not affected by NH4+. Ultra-high-performance liquid chromatography coupled with time-of-flight mass spectrometry was used to separate and identify the transformation products (TPs)converted by photodegradation of penoxsulam in an aqueous solution under UV-Vis (290-800 nm) irradiation. Seven major transformation products were identified based on mass spectral data. The structure was determined by elemental composition calculations, comparison of structural analogs, and existing literature. The main pathways of photodegradation were found to be sulfonamide bond cleavage, rearrangement, triazole ring cleavage, and hydroxylation. These findings are critical to elucidate the environmental fate of penoxsulam in aquatic ecosystems and provide a basis for further environmental risk assessment.

A New "Quasi-Dynamic" Method for Determining the Hamaker Constant of Solids Using an Atomic Force Microscope.

In order to minimize the effects of surface roughness and deformation, a new method for estimating the Hamaker constant, A, of solids using the approach-to-contact regime of an atomic force microscope (AFM) is presented. First, a previous "jump-into-contact" quasi-static method for determining A from AFM measurements is analyzed and then extended to include various AFM tip-surface force models of interest. Then, to test the efficacy of the "jump-into-contact" method, a dynamic model of the AFM tip motion is developed. For finite AFM cantilever-surface approach speeds, a true "jump" point, or limit of stability, is found not to appear, and the quasi-static model fails to represent the dynamic tip behavior at close tip-surface separations. Hence, a new "quasi-dynamic" method for estimating A is proposed that uses the dynamically well-defined deflection at which the tip and surface first come into contact, dc, instead of the dynamically ill-defined "jump" point. With the new method, an apparent Hamaker constant, Aapp, is calculated from dc and a corresponding quasi-static-based equation. Since Aapp depends on the cantilever's approach speed, vc, and the AFM's sampling resolution, δ, a double extrapolation procedure is used to determine Aapp in the quasi-static (vc → 0) and continuous sampling (δ → 0) limits, thereby recovering the "true" value of A. The accuracy of the new method is validated using simulated AFM data. To enable the experimental implementation of this method, a new dimensionless parameter τ is introduced to guide cantilever selection and the AFM operating conditions. The value of τ quantifies how close a given cantilever is to its quasi-static limit for a chosen cantilever-surface approach speed. For sufficiently small values of τ (i.e., a cantilever that effectively behaves "quasi-statically"), simulated data indicate that Aapp will be within ∼3% or less of the inputted value of the Hamaker constant. This implies that Hamaker constants can be reliably estimated using a single measurement taken with an appropriately chosen cantilever and a slow, yet practical, approach speed (with no extrapolation required). This result is confirmed by the very good agreement found between the experimental AFM results obtained using this new method and previously reported predictions of A for amorphous silica, polystyrene, and α-Al2O3 substrates obtained using the Lifshitz method.

High interfacial activity of polymers "grafted through" functionalized iron oxide nanoparticle clusters.

The mechanism by which polymers, when grafted to inorganic nanoparticles, lower the interfacial tension at the oil-water interface is not well understood, despite the great interest in particle stabilized emulsions and foams. A simple and highly versatile free radical "grafting through" technique was used to bond high organic fractions (by weight) of poly(oligo(ethylene oxide) monomethyl ether methacrylate) onto iron oxide clusters, without the need for catalysts. In the resulting ∼1 µm hybrid particles, the inorganic cores and grafting architecture contribute to the high local concentration of grafted polymer chains to the dodecane/water interface to produce low interfacial tensions of only 0.003 w/v % (polymer and particle core). This "critical particle concentration" (CPC) for these hybrid inorganic/polymer amphiphilic particles to lower the interfacial tension by 36 mN/m was over 30-fold lower than the critical micelle concentration of the free polymer (without inorganic cores) to produce nearly the same interfacial tension. The low CPC is favored by the high adsorption energy (∼10(6) kBT) for the large ∼1 µm hybrid particles, the high local polymer concentration on the particles surfaces, and the ability of the deformable hybrid nanocluster cores as well as the polymer chains to conform to the interface. The nanocluster cores also increased the entanglement of the polymer chains in bulk DI water or synthetic seawater, producing a viscosity up to 35,000 cP at 0.01 s(-1), in contrast with only 600 cP for the free polymer. As a consequence of these interfacial and rheological properties, the hybrid particles stabilized oil-in-water emulsions at concentrations as low as 0.01 w/v %, with average drop sizes down to 30 µm. In contrast, the bulk viscosity was low for the free polymer, and it did not stabilize the emulsions. The ability to influence the interfacial activity and rheology of polymers upon grafting them to inorganic particles, including clusters, may be expected to be broadly applicable to stabilization of emulsions and foams.

Modified montmorillonite clay microparticles for stable oil-in-seawater emulsions.

Environmentally benign clay particles are of great interest for the stabilization of Pickering emulsions. Dodecane-in-synthetic seawater (SSW) emulsions formed with montmorillonite (MMT) clay microparticles modified with bis(2-hydroxyethyl)oleylamine were stable against coalescence, even at clay concentrations down to 0.1% w/v. Remarkably, as little as 0.001% w/v surfactant lowered the hydrophilicity of the clay to a sufficient level for stabilization of oil-in-SSW emulsions. The favorable effect of SSW on droplet size reduction and emulsion stability enhancement is hypothesized to be due to reduced electrostatic repulsion between adsorbed clay particles and a consequent increase in the continuous phase (an aqueous clay suspension) viscosity. Water/oil (W/O) emulsions were inverted to O/W either by decreasing the mass ratio of surfactant-to-clay (transitional inversion) or by increasing the water volume fraction (catastrophic inversion). For both types of emulsions, coalescence was minimal and the sedimentation or creaming was highly correlated with the droplet size. For catastrophic inversions, the droplet size of the emulsions was smaller in the case of the preferred curvature. Suspensions of concentrated clay in oil dispersions in the presence of surfactant were stable against settling. The mass transfer pathways during emulsification of oil containing the clay particles were analyzed on the droplet size/stability phase diagrams to provide insight for the design of dispersant systems for remediating surface and subsurface oceanic oil spills.

Synergistic formation and stabilization of oil-in-water emulsions by a weakly interacting mixture of zwitterionic surfactant and silica nanoparticles.

Oil-in-water emulsions were formed and stabilized at low amphiphile concentrations by combining hydrophilic nanoparticles (NPs) (i.e., bare colloidal silica) with a weakly interacting zwitterionic surfactant, caprylamidopropyl betaine, to generate a high hydrophilic-lipophilic balance. The weak interaction of the NPs with surfactant was quantified with contact angle measurements. Emulsions were characterized by static light scattering to determine the droplet size distributions, optical photography to quantify phase separation due to creaming, and both optical and electron microscopy to determine emulsion microstructure. The NPs and surfactant acted synergistically to produce finer emulsions with a greater stability to coalescence relative to the behavior with either NPs or surfactant alone. As a consequence of the weak adsorption of the highly hydrophilic surfactant on the anionic NPs along with the high critical micelle concentration, an unusually large surfactant concentration was available to adsorb at the oil-water interface and lower the interfacial tension. The synergy for emulsion formation and stabilization for the two amphiphiles was even greater in the case of a high-salinity synthetic seawater aqueous phase. Here, higher NP adsorption at the oil-water interface was caused by electrostatic screening of interactions between (1) NPs and the anionic oil-water interface and (2) between the NPs. This greater adsorption as well as partial flocculation of the NPs provided a more efficient barrier to droplet coalescence.

New models and predictions for Brownian coagulation of non-interacting spheres.

The classical steady-state Smoluchowski model for Brownian coagulation is evaluated using Brownian Dynamics Simulations (BDS) as a benchmark. The predictions of this approach compare favorably with the results of BDS only in the dilute limit, that is, for volume fractions of φ≤5×10(-4). From the solution of the more general unsteady-state diffusion equation, a new model for coagulation is developed. The resulting coagulation rate constant is time-dependent and approaches the steady-state limit only at large times. Moreover, in contrast to the Smoluchowski model, this rate constant depends on the particle size, with the transient effects becoming more significant at larger sizes. The predictions of the unsteady-state model agree well with the BDS results up to volume fractions of about φ=0.1, at which the aggregation half-time predicted by the Smoluchowski model is five times that of the BDS. A new procedure to extract the aggregation rate constant from simulation results based on this model is presented. The choice of the rate constant kernel used in the population balance equations for complete aggregation is also evaluated. Extension of the new model to a variable rate constant kernel leads to increased accuracy of the predictions, especially for φ≤5×10(-3). This size-dependence of the rate constant kernel affects particularly the predictions for initially polydisperse sphere systems. In addition, the model is extended to account in a novel way for both short-range viscous two-particle interactions and long-range many-particle Hydrodynamic Interactions (HI). Predictions including HI agree best with the BDS results. The new models presented here offer accurate and computationally less-intensive predictions of the coagulation dynamics while also accounting for hydrodynamic coupling.

Dissipation of pyraclostrobin and its metabolite BF-500-3 in maize under field conditions.

The dissipation and residue of pyraclostrobin and its metabolite BF-500-3 in maize under field conditions were investigated. A sensitive, simple and fast method for simultaneous determination of pyraclostrobin and BF-500-3 in maize matrix was established by high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). The average recoveries of pyraclostrobin and BF-500-3 were found in the range of 83.6-104.9% with relative standard deviations (RSDs) of 2.3-10.0%. The results showed that pyraclostrobin dissipated quickly in maize plant with half-lives of 1.6-1.7 days. Its metabolite BF-500-3 showed a tendency of rapid increasing initially and decreasing afterwards. At harvest time, the terminal residues of pyraclostrobin were below the maximum residue limit (MRL) set by USA and Canada in maize grain when measured 7 days after the final application, which suggested that the use of this fungicide was safe for humans. The results could provide guidance to safe and reasonable use of pyraclostrobin in agriculture.

Multi-residue determination of plant growth regulators in apples and tomatoes by liquid chromatography/tandem mass spectrometry.

A sensitive and rapid multi-residue analytical method for plant growth regulators (PGRs) (i.e., chlormequat, mepiquat, paclobutrazol, uniconazole, ethephon and flumetralin) in apples and tomatoes was developed using high-performance liquid chromatography/tandem mass spectrometry (HPLC/MS/MS). A homogenised sample was extracted with a mixture of methanol/water (90:10, v/v) and adjusted to pH <3 with formic acid. Primary secondary amine (PSA) adsorbent was used to clean up the sample. The determination was performed using electrospray ionisation (ESI) and a triple quadrupole (QqQ) analyser. Under the optimised method, the results showed that, except for ethephon, the recoveries were 81.8-98.1% in apples and tomatoes at the spiked concentrations of 0.005 to 2 mg/kg, with relative standard deviations (RSDs) of less than 11.7%. The limits of quantification (LOQs) were lower than their maximum residue limits (MRLs). The procedure was concluded as a practical method to determine the PGR residues in fruit and vegetables and is also suitable for the simultaneous analysis of the amounts of samples for routine monitoring. The analytical method described herein demonstrates a strong potential for its application in the field of PGR multi-residue analysis to help assure food safety.

Effect of Triton X-100 on the stability of aqueous dispersions of copper phthalocyanine pigment nanoparticles.

The effect of Triton X-100 on the colloidal dispersion stability of CuPc-U (unsulfonated and hydrophobic) and CuPc-S (surface sulfonated and hydrophilic) particles in aqueous solutions (water and NaNO(3)) was investigated at 25 °C. Its adsorption density was determined from surfactant concentrations analyzed by an HPLC method with a UV detector. The experimental dispersion stability ratios of the particles were determined from dynamic light scattering (DLS) data, with the Rayleigh-Debye-Gans (RDG) light scattering theory. The adsorption densities of Triton X-100 on both the CuPc-U and CuPc-S increase with increasing concentration of surfactant up to the critical micelle concentration (cmc), and then reach a plateau. The maximum adsorption density Γ(m) is higher for the CuPc-U (d(h)=160 nm) than that for the CuPc-S (d(h)=90 nm). The hydrophobic chains are inferred to be adsorbed onto the surfaces, and the hydrophilic ethylene oxide chains are in a coil conformation. The W(app)-values for the CuPc-U dispersions are affected mainly by the surfactant fractional surface coverage θ. Adding NaNO(3) has no significant effect on the dispersion stability. The stabilization mechanism for the CuPc-U is inferred to be primarily steric, as expected. The stability ratios for the CuPc-S in solutions with NaNO(3) are higher than those for CuPc-U, and decrease with increasing concentration of NaNO(3), indicating that the stabilization is affected by the screening of electrostatic repulsive forces. The zeta potential is not a good predictor of the electrostatic stabilization, pointing to the need for new and improved theories.

Colloidal dispersion stability of CuPc aqueous dispersions and comparisons to predictions of the DLVO theory for spheres and parallel face-to-face cubes.

The dispersion stability and the zeta potentials of nonspherical crystalline (beta-form) copper phthalocyanine (CuPc) particles of hydrodynamic diameter d(h) approximately = 90 nm were investigated at 25 degrees C in water and in aqueous solutions of NaNO(3). The electrolyte concentrations c ranged from 1 to 500 mM and the particle concentrations ranged from 50 to 10,000 ppm (0.005 to 1 wt %). In each case, the Fuchs-Smoluchowski stability ratio W was determined from dynamic light scattering (DLS) data and the Rayleigh-Debye-Gans (RDG) scattering theory. The data suggest that electrostatic effects play a major role in the stability of CuPc-based dispersions. The calculated particle charge z per CuPc particle based on the zeta potential data and the area of the particles (assumed to be cubical) suggests that there is preferential adsorption of NO(3)(-) ions on the uncharged CuPc surface, and the surface charge increases with increasing electrolyte concentration. Furthermore, two new models of the DLVO theory, for spheres and for parallel face-to-face cubes, were reformulated in dimensionless form. The Hamaker constant of CuPc particles was calculated by the same authors on the basis of theoretical models in J. Chem. Theory Comput. (2010, in press). The key dimensionless group is the ratio N of the electrostatic double layer energy to the Hamaker constant. The two DLVO models were used to predict the value of a dimensionless maximum potential energy Phi(max), the conditions when it may exist, and then the value of W. In water, the DLVO model for spheres overpredicted the stability, while the model for cubes underpredicted the stability. At c = 1 mM, both models overpredicted the stability. At c = 10 mM, the model for spheres underpredicted the stability, whereas the model for cubes overpredicted the stability. Hence, there seems to be some significant shape effects on the electrostatic stabilization of CuPc particle dispersions. At c = 100 and 500 mM, both models underpredicted the stability substantially, suggesting the existence of additional short-range repulsive forces, which may primarily control the stability. Simple sensitivity analysis on the calculations supported these conclusions.

Computation of Nonretarded London Dispersion Coefficients and Hamaker Constants of Copper Phthalocyanine.

A time-dependent density functional theory (TDDFT) scheme has been validated for predictions of the dispersion coefficients of five molecules (H2O, NH3, CO2, C6H6, and pentane) and for predictions of the static dipole polarizabilities of three organometallic compounds (TiCl4, OsO4, and Ge(CH3)4). The convergence of grid spacing has been examined, and two types of pseudopotentials and 13 density functionals have been tested. The nonretarded Hamaker constants A11 are calculated by employing a semiempirical parameter a along with the standard Hamaker constant equation. The parameter a is optimized against six accurate Hamaker constants obtained from the full Lifshitz theory. The dispersion coefficients of copper phthalocyanine CuPc and CuPc-SO3H are then computed. Using the theoretical densities of ρ1 = 1.63 and 1.62 g/cm(3), the Hamaker constants A11 of crystalline α-CuPc and ß-CuPc are found to be 14.73 × 10(-20) and 14.66 × 10(-20) J, respectively. Using the experimentally derived density of ρ1 = 1.56 g/cm(3) for a commercially available ß-CuPc (nanoparticles of ∼90 nm hydrodynamic diameter), A11 = 13.52 × 10(-20) J is found. Its corresponding effective Hamaker constant in water (A121) is calculated to be 3.07 × 10(-20) J. All computed A11 values for CuPc are noted to be higher than those reported previously.

[Bacterial biodiversity in the groundwater contaminated by oil].

An oil-contaminated groundwater sample was collected at an abandoned petrochemical factory.Bacterial genome DNA was extracted for the 16S rDNA gene amplification,and then a bacterial 16S rDNA gene clone library was constructed. After the phylogenetic analysis of 16S rDNA sequences, bacterial diversity and community structure of the groundwater were studied. The results showed the bacteria in the groundwater could be divided into 10 groups, which were as follows: gamma-Proteobacteria (49.1%), alpha-Proteobacteria (12.9%), beta-Proteobacteria (11.1%), Bacteroidetes (9.2%), Verrucomicrobia (6.7%), Acidobacteria (2.5%), delta-Proteobacteria (1.2%), Actinobacteria (1.2%), Planctomycetes (0.6%), unidentified bacteria (5.5%). Gamma-Proteobacteria was predominant in the ecosystem (near 50% of total clones), and especially Pseudomonas accounted for 35.6% of all bacteria. Many clones also affiliated with other degrading bacteria,such as Sphingomornas, Rhodococcus, Brevundimonas. Furthermore, a lot of 16S rDNA sequences in the clone library had high similarity to the ones originated from similar polluted environments, such as soil and groundwater contaminated with chlorinated hydrocarbon, soil and groundwater contaminated with polycyclic aromatic hydrocarbon, soil contaminated with PCBs, antibiotics production wastewater and activated sludge, which proved that there were lots of degrading bacteria population in the oil-contaminated water.

Target control of cell disruption to minimize the biomass electrostatic adhesion during anion-exchange expanded bed adsorption.

Expanded bed adsorption (EBA) is an integrative unit operation for the primary recovery of bioproducts from crude feedstock. Biomass electrostatic adhesion often leads to bad bed stability and low adsorption capacity. The results indicate that effective cell disruption is a potential approach to reduce the biomass adhesion during anion-exchange EBA. Two common cell disruption methods (sonication treatment and high-pressure disruption with a French press) were investigated in the present work. The mean size of cell debris reduced dramatically during the cell disruption process, and the absolute value of the zeta potential of cell debris also decreased significantly as the mean size reduced. The biomass transmission index (BTI) obtained through the biomass pulse response experiment was used to quantitatively evaluate the biomass-adsorbent interaction. Combining the influences of zeta potential of adsorbent (zetaA), zeta potential of biomass (zetaB), and biomass mean size (dB), the parameter of (-zetaA.zetaB.dB) was explored as a reasonable indicator of biomass adhesion in expanded beds. A good linear correlation was confirmed between BTI and (-zetaA.zetaB.dB) for all biomass and cell disruption conditions tested, which was independent of the cell disruption methods. A target parameter (-zetaA.zetaB.dB) of 120 mV2mum was derived for BTI above 0.9, which meant a very slight influence of biomass on the stability of the expanded bed. This criterion could be used as a rational control target for cell disruption processes in EBA applications.