Filter-aid materials are disclosed herein, and processes, systems, and methods using such filter-aid materials for filtering and removing particles and/or constituents from a fluid, wherein the filter-aid material comprises at least one filterable composite adsorbent comprising at least one adsorbent component formed in-situ on at least one filtration component. Further disclosed herein are filter-aid materials and processes, systems, and methods using such filter-aid materials for filtering and removing particles and/or constituents from a fluid, wherein the filter-aid material comprises at least one filterable composite adsorbent comprising at least one adsorbent component formed in-situ on at least one filtration component, and wherein the filter-aid material further comprises an at least one additional filtration component mixed with the at least one filterable composite adsorbent.