Zinc oxide nanoparticles (ZnO NPs) were successfully synthesized by a green method using rosin and zinc chloride as salt precursors. The phase structure, morphology, and particle size of ZnO were determined by X-ray powder diffraction, field emission scanning electron microscopy, and high-resolution transmission electron microscopy. The fabricated ZnO NP samples are crystalline with a grain size of 30–100 nm. The ZnO NPs were used as catalysts for the photodegradation of methylene blue (MB) and methyl orange (MO) under visible and UV light. The results indicate that the prepared ZnO material excellently removed MB and MO (c_initial = 10 mg/L) with efficiencies of 100% and 82.78%, respectively, after 210 min under UV radiation with a ZnO NP dose of 2 g/L. The photocatalyst activity of the synthesized material was also tested under visible light radiation with the same conditions; however, it achieved lower efficiencies. In addition, ZnO NPs were also tested regarding their antibacterial activity, and the results showed that the prepared ZnO samples had the highest (i.e., 100%) antibacterial efficiency against E. coli.

A series of semi-interpenetrating polymer network (semi-IPN) hydrogels based on N,N’-diethylacrylamide (DEA) and itaconamic acid (IAM) were synthesized by changing the molar ratio of linear copolymer P(DEA-co-IAM) and DEA monomer. Linear copolymer P(DEA-co-IAM) was introduced into a solution of DEA monomer to prepare pH-thermo dual responsive P(DEA-co-IAM)/PDEA semi-IPN hydrogels. The thermal gravimetric analysis (TGA) revealed that the semi-IPN hydrogel has a higher thermal stability than the conventional hydrogel, while the interior morphology by scanning electron microscopy (SEM) showed a porous structure with the pore sizes could be controlled by changing the ratio of linear copolymer in the obtained hydrogels. The oscillatory parallel-plate rheological measurements and compression tests demonstrated a viscoelastic behavior and superior mechanical properties of the semi-IPN hydrogels. Besides, the lower critical solution temperature (LCST) of the linear copolymers increased with the increase of IAM content in the feed, while the semi-IPN hydrogels increased LCSTs with the increase of linear copolymer content introduced. The pH-thermo dual responsive of the hydrogels was investigated using the swelling behavior in various pH and temperature conditions. Finally, the swelling and deswelling rate of the hydrogels were also studied. The results indicated that the pH-thermo dual responsive semi-IPN hydrogels were synthesized successfully and may be a potential material for biomedical, drug delivery or absorption applications. The further applications of semi-IPN hydrogels are being conducted.

Detecting toxic transition metal ions using carbon dots (CDs) as fluorescent probes is efficient and sensitive, yet the rational design of CDs with controlled composition and tunable sensing selectivity remains a key challenge. Herein, we report the one-step, solvent-free pyrolysis synthesis of novel fluorescent Cu,N-co-doped carbon dots (Cu,N-CDs) from two aromatic precursors, p-aminosalicylic acid (PAS) and copper(II) acetylacetonate (Cu(acac)₂), under mild conditions (170 °C, 3 h). The resultant Cu,N-CDs exhibited strong green fluorescence with a maximum emission at 495 nm under excitation at 395 nm and a quantum yield of 14.9%. Without further surface modification, these Cu,N-CDs demonstrated high performance as dual fluorescent probes for the simultaneous detection of Fe(III) and Cr(VI) ions. Upon excitation at 395 nm, introduction of either Fe(III) or Cr(VI) at 100 µM resulted in pronounced fluorescence quenching by factors of 50.3 and 3.53, respectively, through two mechanistically distinct pathways: Fe(III) quenching proceeds via formation of a non-fluorescent coordination complex with surface functional groups of the Cu,N-CDs, while Cr(VI) quenching arises primarily from the inner filter effect. The Cu,N-CDs offered high selectivity with low limits of detection for Fe(III) (1.48 µM) and Cr(VI) (19.6 nM). The scalable, solvent-free synthetic strategy and the dual-analyte sensing capability demonstrated here position these Cu,N-CDs as promising platforms for practical deployment in environmental water monitoring, food safety screening for detection of heavy metal pollutants.