Time 0 hBed volumes 0Outlet 0 mg/L (0 %)EBCT 0 minMTZ 0 mService life –Bed used 0 %loadingFPS 0

Drag to orbit, wheel or pinch to zoom. Amber = contaminant, blue = clean water. Granules turn amber as they fill; the glowing band is the mass-transfer zone moving down the bed. Bottom-right: pore-scale view of a granule at the probe height.

Activated Carbon Column: Breakthrough and Mass-Transfer Zone

Contaminated water flows down through porous carbon granules. Watch the adsorption front travel, the filter saturate and the outlet concentration break through - then choose settings that meet a service-life target.

Operation

Carbon and contaminant

Time and probe

Live readouts

Breakthrough curve (outlet C/C0)

Profile along the bed

Missions (predicted from the same model)

Pick a mission, then adjust bed length, flow, granule size and carbon to reach the target service life.

Independent numerical checks

Controls

Drag / one finger: orbit; wheel / pinch: zoom. The Camera button cycles hero, bed close-up and side views.
Flow Q and bed length L set the empty-bed contact time EBCT = L / u. Granule size dp changes how fast molecules reach the inner pores (k_LDF ~ 1/dp²).
K and q_max describe the Langmuir isotherm: how strongly and how much the carbon holds. Feed concentration C0 is the contaminant strength.
Sim speed is simulated minutes per real second (the solver is implicit and stable at any speed). The probe slider chooses which depth the pore-scale inset shows.

The science

Fixed-bed balance. With axial convection and no dispersion: ε ∂c/∂t + u ∂c/∂z + ρ_b ∂q/∂t = 0, where c is the liquid concentration (mg/L), q the carbon loading (mg/g), u the superficial velocity, ε the bed void fraction and ρ_b the bulk density of the carbon.

Isotherm and kinetics. Equilibrium is Langmuir, q* = q_max K c / (1 + K c). Mass transfer into the pores uses the linear driving force model ∂q/∂t = k (q* − q) with k = k_ref (2 mm / d_p)² (intraparticle diffusion control; k_ref is a model value, not a measurement).

Ideal front. A perfectly sharp front would break through at t_st = L (ε + ρ_b q*(C0)/C0) / u. The real curve is smeared by finite k; the length of bed between C/C0 = 5 % and 95 % is the mass-transfer zone (MTZ). The area above the breakthrough curve always equals t_st (mass conservation) - used as a check.

Numerics. 120 cells, upwind, solved implicitly cell by cell with Newton iterations, so it is stable for any time step and conserves mass to rounding error.

Simplifications. No axial dispersion, one dissolved species, no competition between compounds, no biological activity, no temperature change, constant flow, parameters are illustrative model values (typical orders of magnitude only [перевірити за джерелом] before any real design). Educational virtual column: not for designing or operating real treatment plants. Models built with Blender, scene by Three.js.