Deposition of gold nanoparticles on β-FeOOH nanorods for detecting melamine in aqueous solution

Recent advances in environmentally benign hierarchical inorganic nano-adsorbents for the removal of poisonous metal ions in water: a review with mechanistic insight into toxicity and adsorption

Recent developments in nanoscience and technology have addressed many of the problems associated with water quality. Accordingly, using the technological outputs of the recent research on nanomaterials, the best solution for the purification of water is highlighted in this review. Herein, the main objective is to provide mechanistic insight into the synthesis of various inorganic nanoadsorbents and their adsorption chemistry for poisonous metal ions present in polluted water. Initially, the toxicity and carcinogenicity of As3+, Pb2+, Cr6+, Cd2+, and Hg2+ metal ions are highlighted. For the removal of these toxic ions, this review focuses on eco-friendly nanoadsorbents. The various preparation procedures utilized for the preparation of nanoadsorbents are briefly discussed. Generally, this is because of the adsorption capacity of nanoadsorbents depends on their morphology, shape, size, surface area, surface active sites, functional groups, and quantization effect. Also, due to the importance of their mechanism of action, the recent developments and challenges of novel nanoadsorbents such as metal oxides, core shell nanoparticles, magnetic nano ferrates, and functionalized core shell magnetic oxides and the processes for the treatment of water contaminated by toxic metal ions such as As3+, Pb2+, Cr6+, Cd2+, and Hg2+ are exclusively reviewed. Further, the adsorption efficiency of inorganic nanoadsorbents is also compared with that of activated carbon derived from various sources for all the above-mentioned metal ions.

Review on Nanomaterial-Based Melamine Detection

Illegal adulteration of milk products by melamine and its analogs has become a threat to the world. In 2008, the misuse of melamine with infant formula caused serious effects on babies of China. Thereafter, the government of China and the US Food and Drug Administration (FDA) limited the use of melamine of 1 mg/kg for infant formula and 2.5 mg/kg for other dairy products. Similarly, the World Health Organization (WHO) has also limited the daily intake of melamine of 0.2 mg/kg body weight per day. Many sensory schemes have been proposed by the scientists for carrying out screening on melamine poisoning. Among them, nanomaterial-based sensing techniques are very promising in terms of real-time applicability. These materials uncover and quantify the melamine by means of diverse mechanisms, such as fluorescence resonance energy transfer (FRET), aggregation, inner filter effect, surface-enhanced Raman scattering (SERS), and self-assembly, etc. Nanomaterials used for the melamine determination include carbon dots, quantum dots, nanocomposites, nanocrystals, nanoclusters, nanoparticles, nanorods, nanowires, and nanotubes. In this review, we summarize and comment on the melamine sensing abilities of these nanomaterials for their suitability and future research directions.

Cr(vi) removal by mesoporous FeOOH polymorphs: performance and mechanism

The mesoporous FeOOH polymorphs, i.e., goethite (α-FeOOH), akaganeite (β-FeOOH), lepidocrocite (γ-FeOOH), and feroxyhyte (δ-FeOOH) were synthesized and characterized before and after reaction with Cr(vi) using various analytical techniques.