Fig. 3From: Preparation of Graphene Oxide-Based Hydrogels as Efficient Dye Adsorbents for Wastewater TreatmentX-ray diffraction patterns (a) and Raman spectra (b) of GO and lyophilized GO/PEI hydrogels (#2, #3, and #4). c, d D/G and 2D/G ratios of the Raman spectra shown in b, respectivelyBack to article page