Nanoparticle technology is a promising field of interdisciplinary research, which opens up numerous opportunities in various fieldsin the energy and the environment. Hence, potential uses and benefits of such technology are enormous. Our NanotechnologyResearch Group at the University of Calgary has carried out a number of research activities pertaining to the synthesis and directapplication of metal-based nanoparticles for enhanced oil upgrading and recovery, wastewater treatment, and H2S and CO2 capture.Methods for the application of nanoparticle technology in heavy oil processing can be conveniently categorized as in-situ and ex-situapplication. In the in-situ application, resembles the in-situ upgrading and recovery of heavy oil in reservoir, whereby nanoparticlesare directly exposed to real heavy oil feed. In the ex-situ part, resembles the on surface upgrading, nanoparticles are incorporatedand dispersed into support and consequently used in a packed-bed process using real heavy oil feed. In both cases, the presence ofnanoparticles significantly enhanced the upgrading and recovery of heavy oil. For convectional oil recovery enhancement, nanoparticlescould decrease the interfacial tension (IFT) and increase the contact area through the reservoir by improving of sweep efficiency. Othermechanisms by which nanoparticles improve the EOR performance include alteration of rock wettability, changes in permeability andreduction in oil viscosity and mobility ratio. In addition, adding nanoparticles to injecting fluid can also prevent formation damageas nanoparticles may serve as inhibitors for asphaltene precipitation. As for wastewater treatment, nanoparticles functionalized with apetroleum vacuum residue (VR) could be used successfully for removing oil from oil–saltwater emulsions at different ranges of pHvalues. As for H2S and CO2 capture, metal-based nanoparticles could capture sulphur and CO2 and convert them into a chemicallyinactive mineral within the oil reservoir during the upgrading and/or recovery processes.In this talk, we will show the recent findings obtained by our group pertaining to the use of in-house prepared metal-basednanoparticles for enhancing oil upgrading and recovery, wastewater remediation and H2S and CO2 capture. We believe our workin synthesis and application of nanoparticles will provide viable alternate clean technologies for enhancing oil recovery, wastewatertreatment and CO2 capture.