Novel organic sulfide modified bimetallic iron-copper nanoparticle aggregate sorbent materials have been synthesized for removing elemental mercury from vapor streams at elevated temperatures (120-140 degrees C). Silane based (disulfide silane and tetrasulfide silane) and alkyl sulfide based (dibutyl disulfide) organic sulfide precursors were used in the sorbent development. The form and orientation of the organic sulfur molecules were found to play important roles in mercury sorption. In applications involving short contact times for sorbent materials, site accessibility, sorption rate, and dynamic capacity are the critical factors. The synthesized sorbents show high site accessibility and capacity, compared to the widely used sulfur-impregnated activated carbons for mercury removal. The proposed materials and the findings in the study have important industrial and environmental applications (e.g., sorbent materials for mercury removal from flue gases, development of fabric filter liners having extremely high capacity for mercury).