In recent years, biochar has emerged as a remarkable biosourced material for addressing global environmental, agricultural, biomedical, and energy challenges. However, the performances of biochar rest in part on finely tuning its surface chemical properties, intended to obtain specific functionalities. In this review, we tackle the surface treatment of biochar with silane and other coupling agents such as diazonium salts, titanates, ionic/non-ionic surfactants, as well as nitrogen-containing (macro)molecules. We summarize the recent progress achieved mostly in the last five years and correlate the nature and extent of functionalization to eye-catchy end applications of the surface-engineered biochar.

Graphene quantum dots (GQD) is an efficient nanomaterial composed of one or more layers of graphene with unique properties that combine both graphene and carbon dots (CDs). It can be synthesized using carbon-rich materials as precursors, such as graphite, macromolecules polysaccharides, and fullerene. This contribution emphasizes the utilization of GQD-based materials in the fields of sensing, bioimaging, energy storage, and corrosion inhibitors. Inspired by these numerous applications, various synthetic approaches have been developed to design and fabricate GQD, particularly bottom-up and top-down processes. In this context, the prime goal of this review is to emphasize possible eco-friendly and sustainable methodologies that have been successfully employed in the fabrication of GQDs. Furthermore, the fundamental and experimental aspects associated with GQDs such as possible mechanisms, the impact of size, surface alteration, and doping with other elements, together with their technological and industrial applications have been envisaged. Till now, understanding simple photo luminance (PL) operations in GQDs is very critical as well as there are various methods derived from the optical properties of manufactured GQDs can differ. Lack of determining exact size and morphology is highly required without loss of their optical features. Finally, GQDs are promising candidates in the after-mentioned application fields.

Composite-nanofiltration membranes based on polysulfone (PSU) and functionalized graphene oxide (f-GO) were prepared for dye removal from aqueous media. Graphene oxide (GO) was introduced to enhance the performance of these membranes. GO was functionalized using an aminated heterocyclic compound, namely 6-amino-4-(4-nitrophenyl)-3-methyl-4-phenyl-4,7-dihydro-1H-pyrazolo-[3,4-b]pyridine-5carbonitrile. The f-GO was incorporated into the PSU membrane matrix in different weight ratios (0.25, 0.5, 1, 2 and 4 wt %). Characterizing the produced membranes with scanning electron microscope, Fourier Transform Infrared - Attenuated Total Reflectance (FTIR-ATR) and X-ray diffraction indicated the well dispersion of f-GO in the membrane matrix. The obtained membranes were applied to remove Congo red and methylene blue, as typical anionic and cationic dyes respectively from water. The modified membranes showed superior efficiency in terms of water flux and dye rejection upon being compared with the control membrane. The composite membranes loaded with f-GO exhibited promising dye removal efficiency for both dyes.

Nanocomposites of anisaldehyde and salicylaldehyde carboxymethyl chitosan (CMC)-Schiff bases/silver nanoparticles have been prepared and characterized. Their antibacterial activities were evaluated against (Bacillus Subtilis, Staphylococcus aureus and Streptococcus faecalis) as Gram + ve bacteria and the Gram − ve bacteria (Escherichia coli, Neisseria gonorrhoeae and Pseudomonas aeruginosa). The prepared compounds were characterized using FTIR spectroscopy, scanning electron microscopy, transmission electron microscopy and thermogravimetric analysis. Determination of water uptake of both CMC-Schiff bases/silver nanoparticles was carried out. Minimum inhibitory concentrations (MIC) of the prepared nanocomposites were determined as well. Cytotoxic activity of the investigated nanocomposites were evaluated against liver carcinoma cell; HEPG2 and breast cell line; MCF7.