Porous activated carbon (PAC) was synthesized using hard template method from petroleum sludge waste categorized as toxic waste, using mesoporous MCM-41 as silica template. This sludge waste consists of very high carbon content due to the processing and separation's by-product of crude oil and natural gas from the flowing fluids released from the reservoir. The properties of sludge waste was characterized by FTIR to identify the functional group, XRD to determine the crystal structure, SEM-EDX and CS analyzer to perform elemental analysis, as well as determination of moisture content and ash content. The properties of PAC were studied by analyzing the pore size and volume using BET method, and elemental analysis using SEM-EDX and CS analyzer. The elemental analysis results showed that sludge waste consists of 47.10% carbon, indicated it is potential to be converted into activated carbon. The functional group analysis results indicated that sludge waste consists of some functional groups such as hydroxyl, alkene, alkane, and others. The crystal structure analysis results exhibited no crystalline pattern was found, means it could be still in carbon chain form or other amorph compound. The sludge waste has potential to be a good carbon precursor but a template to synthesize porous activated carbon is required. The pore size and volume distribution of PAC in this research is designated to follow the hexagonal arrays possessed by mesoporous MCM-41. The ongoing work shows that this synthesis method is efficient to produce PAC.