Antimicrobial photodynamic therapy is one of the effective strategies for facing the resistance of pathogenic microorganisms of traditional antibiotics. In connection with this, new effective compounds are being sought, increasing their biological activity upon irradiation. In this work, a new polypropylene imine (PPI) from the first generation was synthesized and modified with 1,8-naphthalimide, to which a sulfonyl chloride group (D1) was introduced at the C-4 atom, from which after interaction with glucosamine, a dendrimer containing a sulphonamide group (D2) was obtained. The photophysical characteristics of dendrimer D2 were investigated in five organic solvents of different polarity and aqueous media. It was found that the absorption and fluorescence maxima are slightly affected by the polarity of the solvents. Excimer and monomeric fluorescence were also recorded with dendrimer D2 in an aqueous solution …

The need to conserve water is important, as it is predicted that in approximately 20 years there will be a global water shortage. In Mexico and the rest of the world, scientists are constantly looking for methods to help conserve and improve the processes used to treat the wastewater generated and reuse it safely. In this work, Tilapia fish scales modified with acetic acid were used for the removal of heavy metals from model water. For this experiment, the following adsorbent dose range was applied: 0.4 g to 1 g; the pH ranged from 4 to 7; and the contact time varied between 60 and 120 min. A threefactor experimental design was considered, including variables such as the adsorbent dose, contact time, and pH, each at three levels. The chemical modification produced a more porous surface on the flakes, facilitating metal adsorption, as confirmed by morphological and physicochemical analyses. The results obtained confirmed the removal of 94 and 83% of Cd(II) and Pb(II) metal ions, respectively, with an bioadsorbent dose of 1 g at a pH of 4 and a contact time of 120 min for Cd(II) and an adsorbent dose of 0.4 g, a pH of 4, and a contact time of 90 min for Pb(II), with an initial concentration of 200 mg/L for both metals. The Brunauer–Emmett–Teller (BET) analysis results provide critical insights into the textural properties of modified fish scales. The modified fish scales have great potential for removing heavy metals from industrial wastewater.

This study reports the synthesis and performance of a novel nanocomposite, CS@nZVI-CMC NC, consisting of zero-valent iron nanoparticles cross-linked to chitosan and coated to carboxymethyl cellulose. Also, the novelty of this work has been proven by eliminating several heavy metals and pesticides from aqueous solutions and drinking water simultaneously. The NC structure, morphology, size, and functional groups were investigated using advanced techniques such as TEM, SEM, XRD, FTIR, and BET. It showed that the surface area of the NC is found to be 127.95 m2 /g and a pore volume of 0.659 cm3 /g. A spherical shape of the nanoparticles with an average size of 8 ± 2 nm was obtained. The functional groups of the NC such as the –NH, –OH, –C––O, and –CN were demonstrated using the FTIR analysis. The NC shows 96.91 %, 90.00 %, 60.61 %, 52.73 %, and 40.43 % simultaneous removal of Cr(VI), As(V), Cd(II), Pb(II) and Mn(II), respectively. Also, it demonstrates a significant simultaneous elimination of organochlorine pesticides: DDE, heptachlor, endrin aldehyde, endosulfan, and heptachlor epoxide, being 98.52 %, 94.01 %, 70.98 %, 65.39 %, and 63.02 % the elimination percentage, respectively. In addition, the NC exhibited the highest removal (77.09 %) of parathion methyl when simultaneously removing several organophosphorus pesticides. Adsorption mechanisms for the targeted pollutants were also studied, and adsorption and electron transfer were the predominant mechanisms. Therefore, this novel NC could be a promising water and wastewater treatment adsorbent.