Abstarct: Abstract In this study, the problem of particle filtration in porous media was addressed using the direct-forcing immersed boundary-lattice Boltzmann method (IB-LBM). The research involved investigating three different obstacle shapes (circular, square, and mixed) across three porosity states and varying Reynolds numbers. Three different arrangements with different porosity percentages were adopted for designing the porous media. Among these arrangements, the first arrangement placed the smallest obstacles at the beginning of the porous media, followed by normal-sized obstacles in the second arrangement, and largest obstacles in the third arrangement. The results indicated that circular obstacles demonstrated optimal performance in terms of filtration efficiency within the first arrangement. At a Reynolds number (Re) of 1000, their efficiency ranged from 25.71% to 45.71% as porosity percentage increased within this arrangement. For both square and mixed-shaped (circle + square) obstacles, they exhibited superior performance in the second and third arrangements respectively. In particular, at Re=420, square obstacles showcased an increase in efficiency from 25.71% to 48.57%, while mixed obstacles displayed an efficiency trend of 31.42%, 48.5%, and finally reaching 54.2% under similar conditions. Overall, these findings shed light on how various obstacle shapes and their placement affect particle filtration efficiency within different porosity states across varying Reynolds numbers.