Crossflow Flat-Sheet Membrane Test Cell
Stainless steel SEPA cell housing flat-sheet membrane (effective active area A = 0.0140 m^2).
Chemical & Process Engineering / Crossflow Ultrafiltration
FREE TO EXPLORELABORATORY 23 · CHEMICAL & PROCESS ENGINEERING
Crossflow Membrane Ultrafiltration Permeate Flux & Concentration Polarization
Operate a crossflow membrane ultrafiltration module separating aqueous bovine serum albumin (BSA) protein, measure permeate flux J as a function of transmembrane pressure (TMP), and evaluate membrane hydraulic permeability L_p and gel polarization resistance R_g. Explore interactive transport phenomena, unit operations simulation, and chemical engineering telemetry.
TRANSPORT PHENOMENA · UNIT OPERATIONS · PROCESS CONTROL · REACTION ENGINEERING
Your virtual chemical and process engineering laboratory.
PERMEATE FLUX J—
PROCESS & PILOT PLANT TELEMETRY
Ready to sample with Pressure TMP = 1.5 bar.
Adjust Pressure TMP, then execute chemical process trial.
Chemical and process engineering telemetry is evaluated rigorously using 64-bit IEEE 754 precision. Residuals reflect ordinary least-squares regression across successive observations. Continuous data structures support high-fidelity transport phenomena and unit operations modeling.
Process engineering assumptions and boundary condition limits
The transport and thermodynamic models apply within the specified calibrated operating window (0.5 to 3.0 bar). Evaluated using a 30 kDa MWCO polyethersulfone (PES) flat-sheet membrane (effective area A = 0.0140 m^2) filtering deionized water and 1.0 wt% BSA solution at crossflow velocity v = 1.5 m/s. Linear model relates clean permeate flux J directly to TMP.
Process apparatus & industrial sensors.
High-Pressure Positive Displacement Diaphragm Pump
Delivers feed flow up to 5.0 L/min and pressures up to 10.0 bar with pulsation damper.
Digital Transmembrane Pressure Transducers
Logs feed pressure P_in, retentate pressure P_out, and permeate pressure P_perm with 0.01 bar accuracy.
30 kDa Polyethersulfone (PES) Ultrafiltration Membrane
Asymmetric UF membrane with 30,000 Da MWCO for quantitative BSA protein retention.
Digital Analytical Permeate Balance & Data Logger
Weighs cumulative permeate discharge at 1 Hz with 0.01 g precision to compute real-time flux J.
Thermostatically Controlled Feed Reservoir with Heat Exchanger
Maintains feed solution at constant temperature 25.0 ± 0.1 °C during recirculation.
FOLLOW THE METHOD
A reason behind every step.
Operate a crossflow membrane ultrafiltration module separating aqueous bovine serum albumin (BSA) protein, measure permeate flux J as a function of transmembrane pressure (TMP), and evaluate membrane hydraulic permeability L_p and gel polarization resistance R_g. Standardized parameter settings: 0.5, 1.0, 1.5, 2.0, 2.5, 3.0 bar.
01
Membrane Compaction & Pre-Conditioning
Install a new 30 kDa PES membrane; compact with deionized water at 4.0 bar for 30 minutes until pure water flux stabilizes.
02
Baseline Clean Water Flux Calibration
Set crossflow velocity to 1.5 m/s; record pure water permeate flux J at TMP = 0.5 bar at 25.0 °C.
03
Pressure Stepping Protocol
Step TMP through 1.0, 1.5, 2.0, 2.5, and 3.0 bar, recording steady-state permeate flux J after 10 minutes at each plateau.
04
Protein Solution Introduction
Drain water and charge 2.0 L of 1.0 wt% BSA solution; circulate at TMP = 1.0 bar to establish protein concentration polarization.
05
Flux Decline & Limiting Flux Observation
Measure permeate flux vs TMP for the BSA feed; identify the transition from Darcy linear regime to pressure-independent limiting flux J_lim.
06
Permeability Regression Analysis
Plot clean water permeate flux J versus TMP, fit a linear regression through the origin, and determine membrane permeability L_p.
YOUR NOTEBOOK · 0 OBSERVATIONS
Turn measurements into chemical process engineering insight.
Points are your recorded observations. The solid regression line validates Crossflow Ultrafiltration mathematical scaling.
LINEAR REGRESSION FIT · y = mx + b
J = L_p · TMP = 42.5000 · TMP
| # | Transmembrane Pressure TMP (bar) | Permeate Flux J (L/(m^2·h)) | Transmembrane pressure TMP (bar) | Permeate flux J (L/(m^2·h)) | Remove |
|---|
No readings yet. Execute a process trial and record it.
Calculate it yourself.
CHECK YOUR UNDERSTANDING
Explain what the process engineering metrics mean.
In crossflow ultrafiltration, the transmembrane pressure (TMP) is defined as:
The primary advantage of crossflow filtration over dead-end filtration is:
In the pressure-independent limiting flux regime of ultrafiltration, increasing TMP causes permeate flux to:
A membrane with a Molecular Weight Cut-Off (MWCO) of 30 kDa will reject approximately what percentage of a 66.5 kDa protein (BSA)?
THEORY AND UNIT OPERATIONS CONTEXT
Process engineering background & physical principles.
Membrane separation processes—including microfiltration, ultrafiltration, nanofiltration, and reverse osmosis—are premier pressure-driven unit operations in biotechnology, water desalination, dairy processing, and wastewater reclamation. In crossflow ultrafiltration (UF), pressurized feed slurry recirculates tangentially across the membrane surface at high velocity, while pure solvent permeates perpendicularly through the porous polymeric or ceramic skin (pore size 1 to 100 nm, molecular weight cut-off MWCO 1,000 to 100,000 Da). Retained macromolecular solutes (e.g., proteins, polysaccharides, colloids) accumulate at the membrane boundary layer, forming a concentrated solute layer termed concentration polarization. At low transmembrane pressures (TMP = (P_feed + P_ret - 2 P_perm) / 2), permeate flux J obeys Darcy's law: J = TMP / [μ · R_m] = L_p · TMP, where R_m is clean membrane hydraulic resistance and L_p is pure water permeability. However, as TMP increases, the solute concentration at the membrane surface reaches a critical gel concentration C_g, forming a viscous gel layer that adds dynamic resistance R_g. Beyond this threshold, permeate flux enters the pressure-independent (limiting flux) regime governed by convective-diffusive back-transport: J_lim = k_bl · ln(C_g / C_b), where k_bl is the boundary layer mass transfer coefficient. In this laboratory investigation, an instrumented crossflow flat-sheet ultrafiltration cell with a 30 kDa polyethersulfone (PES) membrane is operated across TMPs from 0.5 to 3.0 bar to measure clean water permeability L_p = 42.5000 L/(m^2·h·bar) and observe the onset of gel polarization.
J = L_p · TMP = 42.5000 · TMP
Evaluated using a 30 kDa MWCO polyethersulfone (PES) flat-sheet membrane (effective area A = 0.0140 m^2) filtering deionized water and 1.0 wt% BSA solution at crossflow velocity v = 1.5 m/s. Linear model relates clean permeate flux J directly to TMP.