The article presents the research carried out for the exploitation of macrophyte seaweed from Black Sea, Romania, as addition in the form of dried and grinded biomass within the pulp slurry in order to improve the quality of the filter paper. The algae Ulva rigida C. Agardh was added in a percentage of 0.5%, 1%, 2%, 4% and 8% (comparatively with the dry material) in the composition of a filter paper with a grammage of 80 g/m2. Concentrations and distribution maps of major and trace elements in marine algae and filter paper with algae mass additions were determined and modeled using: a) Scanning Electron Microscopy (SEM) with Energy Dispersive X-ray Analysis (SEM-EDX) at INPOLDE Research Center, ReForm-UDJG Platform, Faculty of Sciences and Environment, and Electron Microscopy Laboratory at ”Dunarea de Jos” University of Galati (UDJG) and b) Particle induced X-ray emission (PIXE) at Horia Hulubei National Institute for R&D in Physics and Nuclear Engineering (IFIN-HH). Concentration values were corelated with results obtained for selected physical-mechanical characteristics considered important for defining the quality of the filter paper with and without the addition of dry algal biomass.