Access to small size distributions of nanoparticles by microwave-assisted synthesis. Formation of Ag nanoparticles in aqueous carboxymethylcellulose solutions in batch and continuous-flow reactors

Abstract

This article examines the effect(s) of the 2.45-GHz microwave (MW) radiation in the synthesis of silver nanoparticles in aqueous media by reduction of the diaminesilver(i) complex, [Ag(NH(3))(2)](+), with carboxymethylcellulose (CMC) in both batch-type and continuous-flow reactor systems with a particular emphasis on the characteristics of the microwaves in this process and the size distributions. This microwave thermally-assisted synthesis is compared to a conventional heating (CH) method, both requiring a reaction temperature of 100 degrees C to produce the nanoparticles, in both cases leading to the formation of silver colloids with different size distributions. Reduction of the diaminesilver(i) precursor complex, [Ag(NH(3))(2)](+), by CMC depended on the solution temperature. Cooling the reactor during the heating process driven with 390-Watt microwaves (MW-390W/Cool protocol) yielded silver nanoparticles with sizes spanning the range 1-2 nm. By contrast, the size distribution of Ag nanoparticles with 170-Watt microwaves (no cooling; MW-170W protocol) was in the range 1.4-3.6 nm (average size approximately 3 nm). The overall results suggest the potential for a scale-up process in the microwave-assisted synthesis of nanoparticles. Based on the present data, a flow-through microwave reactor system is herein proposed for the continuous production of silver nanoparticles. The novel flow reactor system (flow rate, 600 mL min(-1)) coupled to 1200-Watt microwave radiation generated silver nanoparticles with a size distribution 0.7-2.8 nm (average size ca. 1.5 nm).

Microwave-assisted green synthesis of superparamagnetic nanoparticles using fruit peel extracts: surface engineering, <em>T</em>₂ relaxometry, and photodynamic treatment potential

“…It was hypothesized that the use of MW heating may reduce the reaction time by many orders of magnitude. [30][31][32] We also developed a simple one-pot MW incubation protocol for the attachment of polyethylene glycol (PEGylation) and acidification of bioSPIONs and compared our results with the conventionally used linker-aided procedure using carbodiimide chemistry. The biocompatibility and T 2 relaxivity of the formed pristine and functionalized SPIONs were investigated against those of human cervical epithelial malignant carcinoma (HeLa) cells.…”

Fabrication of silver nanoparticles from leaf extract of Butea monosperma (Flame of Forest) and their inhibitory effect on bloom-forming cyanobacteria

“…Further, silver has been known for its excellent antimicrobial properties and employed as an antiseptic agent in the treatment of wounds and burns [1,2]. There are many physical and chemical methods for the synthesis of SNPs, such as chemical and photochemical reactions [6], thermal decomposition of metal compounds [7], microwaveassisted reduction [8], and laser-mediated reduction [9]. These methods have several demerits specifically high cost and toxicity in the biological system [10].…”

Morphology of Silver Nanoparticles in the Micelle-Forming Block Copolymers

“…To solve this problem, the development of nanoparticle synthesis methods in polymer matrices, which will provide the control of nanoparticle sizes and forms and also their stabilization in a solution, is necessary. In the recent years, many amphiphilic block copolymers, which form reversible micelles in an organic medium, were used to obtain the Ag-containing nanocompositions [10,11]. However, the great interest in terms of the use of silver nanoparticles is their synthesis in aqueous solution as well as …”