Schematic diagram of the sampling chamber.

Heavy metals are a major cause of environmental pollution, and mercury is a well-known toxicant that is extremely harmful to the environment and human health. In this study, new carbon nanotubes coated with cobalt and molybdenum nanoparticles (Co-Mo/MWCNT) were used for Hg0 removal from the air by the amalgamation of solid-phase air removal method (ASPAR). In the bench-scale setup, the mercury vapor in air composition was produced by the mercury vapor generation system (HgGS) and restored in a polyethylene airbag . In optimized conditions, the mercury vapor in the airbag passed through Co-Mo/MWCNT and was absorbed on it. Then, the mercury was completely desorbed from Co-Mo/MWCNT by increasing temperature up to 220 °C and online determined by cold vapor atomic absorption spectrometry (CV-AAS). The recovery and capacity of Co-Mo/MWCNT were obtained at 98% and 191.3 mg g-1, respectively. The Repeatability of the method was 32 times. The mercury vapors absorbed on Co-Mo/MWCNT adsorbent could be maintained at 7 days at the refrigerator temperature. The Co-Mo/MWCNT as a sorbent has many advantages such as; high capacity, renewable, good repeatability and chemical adsorption (amalgamation) of mercury removal from the air. The method was successfully validated by MCA and spiking of real samples.

Aromatic amines are a large group of chemical compounds that have attracted the attention of researchers due to their toxicity and carcinogenicity. This study aimed to develop an efficient method for sampling and analysis of aromatic amines (Aniline, N, N-dimethylaniline, 2-chloroaniline, and 3-chloroaniline) from the vapour phase (headspace) of urine samples. For the implementation of this plan, a needle trap device packed with the three-component adsorbent consisting of nano-Hydroxy Apatite (nHA), Zeolite (Ze), and Metal–Organic Framework (MOF) equipped with GC-FID was employed for the first phase. Examination of the prepared adsorbents was performed by FT-IR, PXRD, and FE-SEM techniques. The optimal value of considerable parameters such as time and temperature of extraction, salt content, and pH were established using the Response Surface Methodology-Central Composite Design (RMS-CCD) method. In this way, the optimal extraction of targeted analytes was accomplished in 41 min at 41 °C with NaCl content of 33.0% (w/v) and pH: 13.0, respectively. Also, the repeatability and reproducibility of the method were calculated to be in the range of 2.2–7.1% and 3.9–8.1%, respectively, which indicates the acceptable precision of the method. Also, the limit of detection (LOD) and limit of quantification (LOQ) were determined in the range of 0.3–32.0 ng.L−1 and 0.8–350.0 ng.L−1, respectively, which proves the high sensitivity of the proposed method. Furthermore, the recovery percent of the extracted analytes was concluded in the range of 97.0–99.0% after 6 and 30 days of the sampling and storage at 25 °C and 4 °C, respectively. Finally, the designed procedure was employed in the analysis of the above-mentioned aromatic amines in the real urine samples. The achieved results illustrate that the three-component absorbent system (nHA;Ze;MOF@NTD) can be introduced as an efficient, fast-response, sensitive, and versatile procedure for trace analysis of the different aromatic amine compounds in public and occupational health.

Schematic image of sampling and analysis of organophosphorus (OPs) compounds by organo-LDH:NTD method.