Resonance Raman characterization of poly(benzidine) in different oxidation states

Multilayered CWO/MXene/PANI-Coated Thermoplastic Expanded Microsphere Sponge for Enhanced Solar Desalination Efficiency

Interfacial solar-driven evaporation (ISDE) is a promising method for addressing the global freshwater shortage. However, it remains challenging to develop an ISDE system that combines high evaporation rates, low cost, ease of processing, and self-floatability. In this study, we present a flexible, porous sponge photothermal material based on three-dimensional thermoplastic expanded microspheres (TEMs). TEMs feature a unique hollow structure, which provides thermal insulation and minimizes heat loss. Flexible porous sponges were selected as the water transport medium in the evaporation zone, while CWO, MXene, and PANI were used as photothermal absorbing coatings on the TEMs. These three photothermal materials possess distinct absorption spectra, allowing for multilayered light absorption and enabling full-spectrum sunlight utilization. The resulting flexible multi-TEMs@PANI/MXene/CWO sponge exhibits excellent properties, including low thermal conductivity, high absorption, and efficient thermal conversion. The system achieved an evaporation rate of 2.07 kg·m-2·h-1 under primary light and a photothermal conversion efficiency of 89.7%. This work offers a controllable, environmentally friendly, and stable strategy to address the pressing issue of freshwater scarcity.

Dispersive magnetic solid phase extraction of triazole fungicides based on polybenzidine/magnetic nanoparticles in environmental samples

A polybenzidine-modified Fe3O4@SiO2 nanocomposite was successfully synthesized through a chemical oxidation method and employed as a novel sorbent in dispersive magnetic solid phase extraction (DMSPE) for the preconcentration and determination of three triazole fungicides (TFs), namely diniconazole, tebuconazole, and triticonazole in river water, rice paddy soil, and grape samples. The synthesis method involved a polybenzidine self-assembly coating on Fe3O4@SiO2 magnetic composite. Characterization techniques such as FT-IR, XRD, FESEM, EDX, and VSM were used to confirm the correctness of the synthesized nano-sorbent. The target TFs were determined in actual samples using the synthesized nanocomposite sorbent in combination with gas chromatography-flame ionization detection (FID). Several variables were carefully optimized , including the sample pH, sorbent dosage, extraction time, ionic strength, and desorption condition (solvent type, volume, and time). Under the optimized experimental conditions, the method exhibited linearity in the concentration range 5-1000 ng mL-1 for triticonazole and 2-1000 ng mL-1 for diniconazole and tebuconazole. The limits of detection (LOD) for the three TFs were in the range 0.6-1.5 ng mL-1. The method demonstrated acceptable precision with intra-day and inter-day relative standard deviation (RSD) values of less than 6.5%. The enrichment factors ranged from 248 to 254. Finally, the method applicability was evaluated by determining TFs in river water, rice paddy soil, and grape samples with recoveries in the range 90.5-106, indicating that the matrix effect was negligible in the proposed DMSPE procedure.

Chemical Oxidative Condensation of Benzidine in Non-Aqueous Medium: Synthesis and Investigation of Oligomers and Polymer with Benzidine Diimine Units

The oxidative condensation of benzidine has been carried out in acetic acid media using potassium peroxydisulfate as the oxidizing agent. Using different monomer–oxidant molar ratios, benzidine dimer, trimer, and polymer have been synthesized for the first time. It was established that the polybenzidine structure is composed from a sequence of benzidinediimine and diphenylene units with amino/amino end groups and thus proves the possibility of ammonia elimination during the oxidative polymerization of aromatic diamines. The method seems to be common for the synthesis of polymers with the sequence of aromatic diimine and arylene units. TGA analysis of the obtained trimer and polymer was investigated, and the high thermostability of both the polymer and trimer was revealed. According to the obtained data, both polymer and trimer matrix decomposition started at 300 °C, and at 600 °C, 75.94% and of 69.40% of the initial weight remained, correspondingly. Conductivities of the polymer and trimer show a semiconductor-type change from temperature and after doping show an increase in conductivity up to 10⁻⁴ Sm/cm.