Herein we demonstrate first report on fabrication, characterization, and adsorptive appraisal of graphene/cellulose nanofibers (GO/CNFs) monolith for methylene blue (MB) dye. Series of hybrid monolith (GO/CNFs) were assembled via urea assisted selfassembly method. Hybrid materials were characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction patterns, Raman spectroscopy, elemental analysis, thermogravimetric curve analysis, specific surface area, surface charge density measurement, and compressional mechanical analysis. It was proposed that strong chemical interaction (mainly hydrogen bonding) was responsible for the formation of hybrid assembly. GO/CNFs monolith showed mechanically robust architecture with tunable pore structure and surface properties. GO/CNFs adsorbent could completely remove trace to moderate concentrations of MB dye and follow pseudo-second-order kinetics model. Adsorption isotherm behaviors were found in the following order: Langmuir isotherm > Freundlich isotherm > Temkin isotherm model. Maximum adsorption capacity of 227.27 mg g −1 was achieved which is much higher than reported graphene based monoliths and magnetic adsorbent. Incorporation of nanocellulose follows exponential relationship with dye uptake capacities. High surface charge density and specific surface area were main dye adsorptive mechanism. Regeneration and recycling efficiency was achieved up to four consecutive cycles with costeffective recollection and zero recontamination of treated water.

Owing to some advantages of high oxidation capacity, high mass-transfer efficiency, high utilisation rate of reagents, simple system for treating pollutants, micro-nanobubble technology (MNBT) has gradually attracted attention and has been successfully applied in environmental pollution control. Currently, its applications in this field are mainly in the aspects of surface water purification, sewage (waste) water treatment, soil and groundwater remediation and sludge treatment which are reviewed. These studies primarily focus on the MNB generation (MNBG) methods, the parameters of pollution treatment and its effect improvement, the coupling techniques of this technology and other advanced oxidation technologies. However, in order to successfully promote its applications to the actual environmental pollution control process, especially the industrial scale, the following efforts are required: covariant response mechanism of water qualitymicro-nano aeration parametersbubble characteristics, further optimisation of synergistic process with other advanced oxidation methods, development of lower energy consumption and more efficient MNBG devices. After discussion and analysis, this work further points out that the purification of exhaust gas such as volatile organic compounds (VOC) and flue gas is one of the research directions worth exploring in the future application of the MNBT.

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