A Unique Interactive Nanostructure Knitting based Passive Sampler Adsorbent for Monitoring of Hg2+ in Water

Abstract

This work reports the development of ultralight interwoven ultrathin graphitic carbon nitride (g-CN) nanosheets for use as a potential adsorbent in a passive sampler (PAS) designed to bind Hg2+ ions. The g-CN nanosheets were prepared from bulk g-CN synthesised via a modified high-temperature short-time (HTST) polycondensation process. The crystal structure, surface functional groups, and morphology of the g-CN nanosheets were characterised using a battery of instruments. The results confirmed that the as-synthesized product is composed of few-layered nanosheets. The adsorption efficiency of g-CN for binding Hg2+ (100 ng mL−1) in sea, river, rain, and Milli-Q quality water was 89%, 93%, 97%, and 100%, respectively, at natural pH. Interference studies found that the cations tested (Co2+, Ca2+, Zn2+, Fe2+, Mn2+, Ni2+, Bi3+, Na+, and K+) had no significant effect on the adsorption efficiency of Hg2+. Different parameters were optimised to improve the performance of g-CN such as pH, contact time, and amount of adsorbent. Optimum conditions were pH 7, 120 min incubation time and 10 mg of nanosheets. The yield of nanosheets was 72.5%, which is higher compared to other polycondensation processes using different monomers. The g-CN sheets could also be regenerated up to eight times with only a 20% loss in binding efficiency. Overall, nano-knitted g-CN is a promising low-cost green adsorbent for use in passive samplers or as a transducing material in sensor applications.

Preparation of Few-Layered Wide Bandgap MoS2 with Nanometer Lateral Dimensions by Applying Laser Irradiation

“…Zhang's group prepared MoS 2 /polyvinylpyrrolidone (PVP) nanocomposites by sonication of MoS 2 powder in ethanol with PVP [16]. So far, the practical application of g-CN has been limited to photocatalytic water splitting, photodegradation of dyes, bioimaging, photocatalyst, and fluorescence applications [17][18][19].…”

Mercury Determination in Natural Zeolites by Thermal Decomposition Atomic Absorption Spectrometry: Method Validation in Compliance with Requirements for Use as Dietary Supplements

“…Also, for Hg monitoring in the environment, several methods and devices have been developed for passive sampling. Chouhan and co-workers [23] have developed a nano-knitted green adsorbent to be used in passive sampler devices for Hg monitoring in water. Taking into account its high toxicity, and in order to protect human health, the Commission Regulation 629 of 2 July, 2008, amending Regulation (EC) No.…”

Emerging tri‐s‐triazine‐based graphitic carbon nitride: A potential signal‐transducing nanostructured material for sensor applications

“…These include its relatively lower bandgap energy of g‐C 3 N 4 (2.7 eV), low specific surface area, low quantum yield because of a limited electronic changeover, and a rapid recombination rate of photogenerated electrons and holes. [ 41–43 ] To circumvent these issues, researchers have tried to improve the optoelectronic properties of g‐C 3 N 4 , through post‐synthetic exfoliation of bulk g‐C 3 N 4 materials to create different morphologies including sheets, [ 44 ] nanorods, [ 45 ] nanotubes, [ 46 ] and quantum dots. [ 47 ]…”

“…Recently, several research groups have been successful in exfoliating a few layers of pristine nanosheets from bulk material using control synthesis methods. [ 44,58–60 ] Two approaches are currently employed for the fabrication of nanosheets: a top‐down approach, and a bottom‐up approach (Figure 3A). [ 61 ] Top‐down approaches include chemical etching and ultra‐sonication‐assisted exfoliation, [ 62,63 ] whereas bottom‐up approaches involve template‐assisted and hetero atom mediated methods.…”

“…So‐called “green” exfoliation methods are an alternative solution for the production of 2D nanosheets, which are on the verge of producing high yields while avoiding harsh chemical treatments. [ 44 ] For example, Yan et al. demonstrated the green exfoliated of ultrathin graphitic carbon nitride nanosheets (CNNS) from bulk g‐C 3 N 4 using hot water (Figure 3B).…”