Based on the ability of some specific aquatic plants to concentrate metals in their roots, we propose an innovative biosorption system to clean up mining effluents. The system we propose represents an interesting solution to an important environmental problem, the decontamination of metal-polluted water and prevention of dispersal of metals into the environment. The solution presented is a form of ecological recycling of Zn, an essential primary metal in many industrial applications. Finally, the methodology developed is a sustainable way of managing the biomass from eradication or control of invasive plants.

In the context of exponentially growing problems of pollution and waste, the design of ecofriendly processes for turning the current treatment of effluents into sustainable catalysts represents a great opportunity. Wastewater arising from pyrite quarrying is selected as a model example. The acidity of pyrite effluents leads to solubilization of useful cations: Mn II and Fe II /Fe III. Their chemical properties are an opportunity to promote innovative studies of oxidation in organic synthesis. The controlled addition of NaOH and a co-oxidant (H 2 O 2) onto the effluents allows generation of new, oxidative catalysts. MP-AES analysis, XPS, XRPD, BET, TEM, HRTEM, and EDX studies were performed to characterize the new and efficient catalysts. Oxidation of alcohols into carbonyl compounds, oxidative cleavage of 1,2diols, and epoxidation of alkenes are described.

p-Menthane-3,8-diol (PMD) is gradually dethroning the synthetic golden standard mosquito repellent, N,N-diethyl-m-toluamide (DEET), as PMD is natural and considered safer while displaying an excellent repellent activity. In this study, we revisited the synthetic route of PMD from citronellal in greener conditions, while maintaining the highest yield, and developed a sustainable post-reaction process. Biosourced ammonium salts were tested to catalyze the carbonyl-ene reaction-hydration transforming citronellal and essential oils rich in citronellal into PMD. Ammonium salts led to excellent conversions and selectivities toward PMD, better than previously reported, even at low catalytic loading and rapidly. Catalytic solution of ammonium salts could be directly reused, up to six times without any loss of activity. The sustainability of the methodology was evaluated using a holistic approach which gave excellent green metrics, such as the PMI (6), TON (708), TOF (17), and E-factor (0.68) in comparison to other processes. The repellent activities of PMD synthesized from citronellal and from essential oils were evaluated against Aedes albopictus, the most invasive mosquito in the world, and were as much or even more repellent than pure PMD.