In this work, we described a simple and effective synthesis method for preparing well-dispersed Pd–graphene nanohybrids through simultaneous chemical reduction of functionalized graphene oxide and Pd²⁺ ions. The structure and physicochemical properties of the resulting nanohybrids were characterized in detail by Fourier transformation infrared spectroscopy, Raman, X-ray photoelectron spectroscopy, high-resolution transmission electron microscopy and scanning electron microscopy. The obtained results indicated that Pd nanoparticles distributed uniformly on the surface of the functionalized graphene when the loading amount of Pd is less than 1.0 wt%. Moreover, the so-formed Pd-FG hybrid material could be well dispersed in water, forming a homogeneous dispersion. This nanohybrid, combining the unique catalytic properties of Pd with the excellent adsorption and electron transfer ability of graphene, exhibited enhanced catalytic activity toward the reduction of 4-nitrophenol by NaBH₄ even under lower Pd loading.

In this study, we present a simple synthetic route for the preparation of narrowly distributed silver nanoparticles by using a phenolic hydroxyl modified chitosan as both reducing and capping agent. The effects of factors such as temperature and the concentration of both chitosan derivative and AgNO₃ were systematically investigated and optimized. It was shown that narrowly distributed silver nanoparticles with an average diameter of 4–5 nm were successfully prepared under the optimal conditions in just few minutes. The structure, morphology and physicochemical properties of the prepared silver nanoparticles were characterized in detail by a series of techniques. The roles of phenolic hydroxyl groups linked by Schiff base in the reduction and stabilization of silver nanoparticles were studied by comparison with a series of chitosan derivatives and the possible mechanism was proposed. These chitosan derivative stabilized silver nanoparticles, combining the unique properties of silver and chitosan, exhibited broad spectrum and excellent antimicrobial performance against different categories of both bacteria and plant fungi.

Herein, we describe an environmentally friendly strategy to synthesize Ag nanoparticles on Nanodiamond (ND) by utilizing natural adhering and reduction properties of tea polyphenols (TPs). Firstly, the surface of ND was modified by TPs through their natural adhering ability. Then, the modified TPs functioned as reducing agents for reducing Ag precursor in situ. The synthesis process, structure and its physicochemical properties of the nanohybrid were tracked and characterized by UV-Vis, FTIR, TGA, HRTEM, XRD and XPS. It has been shown that Ag nanoparticles with uniform size and distribution were anchored successfully on the surface of ND. The ND supported Ag nanoparticles displayed highly water dispersibility due to the hydrophilicity of TPs, as is very important in heterogeneous catalysis. The catalytic performance of this nanohybrid was evaluated comprehensively by catalyzing 4-nitrophenol reduction by sodium borohydride, which is often used as a model reaction, showing excellent catalytic activity and recycling stability. GRAPHICAL ABSTRACT

Modified biomass is a green and renewable sorbent to remove organic pollutants in water. In this study, an efficient bio-based adsorbent was obtained by Fenton-like pretreatment of peanut hull with FeOCl, which can be used to efficiently remove methylene blue from water. The adsorption experiment showed that under the conditions of 25°C, pH 6.0, MB concentration of 100 mg·L⁻¹ and adsorbent dosage of 1.0 g·L⁻¹, the adsorption equilibrium could be achieved within 6 min, with MB removal rate of 85.1% and maximum adsorption capacity of 132 mg·g⁻¹, which was much higher than that of untreated peanut hull (64 mg·g⁻¹). Material characterization showed that Fenton-like pretreatment resulted in the surface morphology change and pore structure formation of peanut hull, and the specific surface area increased significantly, which was an important reason for rapid adsorption. The adsorption mechanism showed that the adsorption of methylene blue followed pseudo second-order models, and conformed to Redlich-Peterson and Langmuir models. According to the thermodynamic analysis results, it is concluded that the adsorption process is endothermic and spontaneous. Adsorption mechanism includes hydrogen bonding, static electricity and van der Waals force. GRAPHICAL ABSTRACT

Laccases can catalyze the remediation of hazardous synthetic dyes in an eco-friendly manner, and thermostable laccases are advantageous to treat high-temperature dyeing wastewater. A novel laccase from Geothermobacter hydrogeniphilus (Ghlac) was cloned and expressed in Escherichia coli. Ghlac containing 263 residues was characterized as a functional laccase of the DUF152 family. By structural and biochemical analyses, the conserved residues H78, C119, and H136 were identified to bind with one copper atom to fulfill the laccase activity. In order to make it more suitable for industrial use, Ghlac variant Mut2 with enhanced thermostability was designed. The half-lives of Mut2 at 50 °C and 60 °C were 80.6 h and 9.8 h, respectively. Mut2 was stable at pH values ranging from 4.0 to 8.0 and showed a high tolerance for organic solvents such as ethanol, acetone, and dimethyl sulfoxide. In addition, Mut2 decolorized approximately 100% of 100 mg/L of malachite green dye in 3 h at 70 °C. Furthermore, Mut2 eliminated the toxicity of malachite green to bacteria and Zea mays. In summary, the thermostable laccase Ghlac Mut2 could effectively decolorize and detoxify malachite green at high temperatures, showing great potential to remediate the dyeing wastewater.