The excess of mango peels is considered manufacturing waste in the sugar and juice industry. There is an increasing interest in looking for alternative ways to employ this waste to address this overload. Here, we show the efficient use of mango peels as a noncost carbon source for the synthesis of graphene. We demonstrate for the first time the synthesis of graphene on Cu substrates from mango peels, a biomass rich in pectin. It is observed that plasma presence is essential for the growth of graphene from mango peels. At 15 and 30 min of plasma exposure, we observed the presence of multilayered graphene, at longer plasma exposure, i.e., 60 min, there is the formation of monolayer graphene, attributed to the etching of multiple layers formed at short times due to long plasma exposure time. When employing this technique, precautions must be taken due to the etching effect of plasma, such as reducing either the plasma exposure time or the plasma power. Finally, we present a graphene growth pathway under plasma environment on the basis of our experimental observations.

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A 23 factorial design was used to evaluate the influence of temperature, catalyst and time and esterification degree (DE) of pectin obtained from mango, orange and tangerine peels as well as tamarind seeds by using the acid hydrolysis method. The study showed that a high temperature positively influenced the percentage of pectin yield for the four second generation biomasses. Nevertheless, the temperature showed a greater influence in the solubility and diffusion of the acid solvent in the tamarind seed matrix, resulting a pectin recovery 32.9%. Concerning the %DE, the most statistically significant value observed was dependent on the type of biomass studied. The %DE and the nature of the pectin are determining factors in the pectin’s final use, in the present work the pectin extracted was used to produce furfural, a precursor of high value chemicals. The furfural production was achieved through alkaline hydrolysis and enhanced using the Maillard reaction, reaching a maximum concentration of 71.8 g/L which represents a 42.1% increase from the alkaline hydrolysis.

Green synthesis is characterized by using plants’ secondary metabolites (S-Met) to reduce metal ions into metallic atoms, which are subsequently nucleated and agglomerated, forming the nanoparticles (NPs). Thereby, the significant diminishing in producing toxic waste during the green synthesis approach may be considered an environmentally friendly alternative. In the present work, titania (TiO2) NPs were greenly synthesized using Ricinus Communis (RC), Moringa Oleifera (MO) or Bougainvillea Spectabilis (BS) plant extracts. Obtained nanoparticles were characterized using XRD, SEM, EDS, BET, XPS and UV-vis techniques. The physicochemical and electronic properties of synthesized nanoparticles were improved concerning the reference material. The surface area increased up to 17 times, accompanied by a decrease in crystal size (∼50%) and gap energy value. Furthermore, the photocatalytic performance of the obtained samples was evaluated in the furfural production from nejayote, an unexplored industrial residual biomass. The furfural yield was twice higher using the sample obtained from the BS metabolites than those obtained with the other S-Met, attributed to the preferable formation of xylose over other pentoses. This work proved the viability of nanomaterial synthesis using common plants abundant in Latin-American applied for the waste transformation coming from an overall process such as nixtamalization, the nejayote.