Thermophoretic transport of colloidal particles in aqueous media, driven by temperature gradients, plays a crucial role in applications such as separation, enrichment, and biochemical sensing. The interplay between colloid size, surface chemistry, electrolyte composition, and background temperature govern thermophoretic behavior, though inconsistencies remain in both theoretical and experimental studies. This work addresses unresolved aspects of colloid thermophoresis, focusing on the size, temperature, and surface chemistry dependencies of the Soret coefficient in aqueous solutions. A mode-coupling model within the Fokker-Planck framework was developed to describe colloid thermophoresis, capturing the contributions of both bulk and interfacial effects. The analysis indicates that, while bulk effects are independent of colloid size, interfacial effects such as electrostatic, hydration entropy, and depletion interactions exhibit distinct size dependencies. For silica microspheres, the ionic shielding effect negatively impacts the Soret coefficient because of the dissociation of terminal silanol groups at the silica-water interfaces, whereas the hydration entropy effect provides a positive contribution. In contrast, polystyrene nanoparticles show positive ionic shielding contributions driven by temperature-dependent variations in Bjerrum length, with hydration entropy interactions exerting a negative influence on the overall Soret coefficient. For protein suspensions of T4 lysozymes, it was shown that the interplay between bulk viscosity effect and interfacial interactions determined the overall Soret coefficient. Surface chemistry effects were further explored in surfactant solutions below the critical micelle concentration (CMC). Silica microspheres in non-ionic surfactants, such as Tween 20 and Triton X-100, exhibited enhanced hydration entropy interactions due to surfactant-assisted silanol dissociation. In anionic surfactant solutions, the adsorption of DS- at the solid-liquid interface governed thermophoretic behavior. For soft surfactant-laden micro-droplets, increasing droplet size with temperature amplified ionic shielding contributions but led to negative hydration entropy effects, driven by charge regulation at the liquid-liquid interface. The findings provide insight into the fundamental mechanisms driving thermophoresis in aqueous colloidal systems, offering pathways for improved separation, enrichment, and biochemical sensing in microfluidic environments.