Nanoparticle Transport Through Soil 2D: Column Cross-Section

2D companion to the 3D colloid-filtration model. Engineered nanoparticles washed into soil don't simply vanish — whether they stay trapped near the surface or travel toward groundwater is governed by colloid filtration theory, the same physics used to design remediation barriers and assess environmental nanosafety. This simulator renders a schematic sand-column cross-section, panned and zoomed freely, and injects nanoparticles that diffuse, settle and attach according to the real Yao (1971) single-collector efficiency model: diffusion dominates for the smallest particles, gravitational settling dominates for the largest, and a well-known "weak spot" around 100–500 nm lets particles slip through most easily. Tune particle size, pore-water velocity, attachment efficiency (a stand-in for ionic strength) and grain size, then watch the live breakthrough curve and filtration coefficient track the physics in real time.