The Hsiao group at Stony Brook has been using a wide range of synchrotron X-ray scattering and spectroscopic techniques to investigate many fundamental aspects of nanocellulose, the nanoscale aggregate of elementary cellulose microfibril (the building block of plant cells). The investigated topics included: (i) the cross-sectional shape and dimensions as well as the aggregation behavior of cellulose microfibrils in suspension and ice-templating processing, (ii) the re-assembly of nanocellulose into high-performance fibers and membranes through hydrodynamic alignment, (iii) the ion-induced gel-transition of nanocellulose scaffolds, where ions act as screening or cross-linking agents depending on the valency, (iv) nanoscale dynamics of metallic nanoparticles in networks of charge stabilized nanocellulose. Recently, our team has developed the zero-waste nitro-oxidation process (NOP) to prepare nanocellulose from biomasses of diverse origins, where these synchrony X-ray technologies have allowed us to rapidly develop a wide range of new materials from water/nutrient retention soil conditioners, peat-replacing growing media, water purification agents and filters, to construction material additives. The demonstrated NOP technology has many far-reaching impacts to provide new circular solutions to improve the nexus of food-water-infrastructural systems.