Surface modification of coconut shell activated carbon for efficient solid‐phase extraction of N‐nitrosodimethylamine from water

Abstract

A practical and cheap methodology in modifying commercial coconut shell activated carbon for solid‐phase extraction of N‐nitrosodimethylamine in water was developed through an understanding of activated carbon surface chemistry. In comparison with commercial activated carbon, extraction recoveries by activated carbon treated with sulfuric acid decreased by 50%, while those of activated carbon heated at 800°C improved by more than 100%. Acid treatment increased the oxygen content on the carbon's surface. In contrast, heat treatment decreased the surface oxygen content, resulting in a more hydrophobic surface, which favoured adsorption and extraction of N‐nitrosodimethylamine. The influence of different activated carbon sizes, amount of modified activated carbon, and pH on the N‐nitrosodimethylamine recoveries was assessed and compared with the commercial solid‐phase extraction cartridge. The recommended amount of powder activated carbon treated at 800°C was 3 g to yield an optimum recovery of 130%, which was superior to the commercial solid‐phase extraction cartridges. The method validation results confirmed the high accuracy, reproducibility, and precision of the method. The study indicated that chemisorption plays a significant role in the adsorption of N‐nitrosodimethylamine on activated carbon, and the optimization of its surface chemistry can enhance N‐nitrosodimethylamine adsorption/extraction from water.

Contaminants of emerging concerns (CECs) in a municipal wastewater treatment plant in Indonesia

“…The SPE was conducted for the target CECs except for NDMA (twenty-one CECs), employing Oasis HLB cartridges with the protocol mentioned in our earlier published work (Astuti et al 2022 ). For NDMA, the SPE was conducted using Supelco Coconut Charcoal SPE cartridges according to SPE procedures stated in our previous published work (Astuti et al 2021 ). However, due to difficulty procuring new NDMA stock, the compound was not spiked during the SPE; hence, the analysis for NDMA was performed only to check its presence or absence in the sample (detect/non-detect).…”

Photodegradation and adsorption of hexazinone in aqueous solutions: removal efficiencies, kinetics, and mechanisms

“…In this study, CSGAC was used as an adsorbent to perform the adsorption tests. The characterizations of the adsorbent have been presented in our previous work and are as follows: BET surface area (984 m 2 g −1 ), micropore volume (0.39 m 3 g −1 ), mesopore volume (0.029 m 3 g −1 ), elemental analysis for carbon (85.9%), oxygen (10.7%), hydrogen (0.8%), nitrogen (< 0.3%), sulfur (< 0.3%), and total ash content (2.6%) (Astuti et al 2021 ). The adsorbent was first washed with Milli-Q water and then dried at 110 °C in an oven for 24 h (Yu et al 2016 ).…”

Preparation of flower‐like molybdenum disulfide for solid‐phase extraction of N‐nitrosoamines in environmental water samples

“…The sample pH affects the presence state of targets and the surface charge of adsorbents. In order to obtain the optimum extraction efficiency, the effects of different pH values (3)(4)(5)(6)(7)(8)(9)(10)(11) adjusted by formic acid and aqueous ammonia on the recoveries of NAs were investigated, respectively. As seen in Figure 4B, the recoveries increased with the pH value from 3 to 7 and gradually decreased when the pH value further increased from 7 to 11.…”

“…Thus, pre-concentration and purification are necessary before NAs are detected. The commonly used pretreatment techniques for NAs mainly include liquidliquid extraction [8] and SPE [9,10]. Compared with liquidliquid extraction, SPE possesses advantages of easy operation, high enrichment factors, effectively removing interferences, and reducing consumption of organic solvents [11].…”