Article Name:

Rapid removal of heavy metal ions from aqueous solution by low cost adsorbents.

Abstract: 

In the present investigation, different agricultural solid wastes namely: eggplant hull (EH), almond green hull (AGH), and walnut shell (WS), that are introduced as low cost adsorbents, were used for the removal of heavy metals (cobalt, strontium and mercury ions) from aqueous solutions. Activation process and/or chemical treatments using H2O2 and NH3 were performed on these raw materials to increase their adsorption performances. The effectiveness of these adsorbents was studied in batch adsorption mode under a variety of experimental conditions such as: different chemical treatments, various amounts of adsorbents, initial metal-ion concentrations, pH of solutions, contact times, and solution temperatures. High metal adsorption efficiencies were achieved for all cases only in the first two to three minutes of adsorbents’ contact time.
Maximum adsorption capacity of AGH sorbent for cobalt and EH for mercury were found to be 45.5 mg/g and 147.06 mg/g, respectively. The adsorption capacity of mercury for WS was also obtained as 151.5 and 100.9 mg/g for two different treated sorbents.

Reference:

Ahmadpour, A., Rohani Bastami, T., Tahmasbi, M., & Zabihi, M. (2012). Rapid removal of heavy metal ions from aqueous solutions by low cost adsorbents. International journal of global environmental issues, 12(2-4), 318-331.

Keywords:
Envirounment, Heavy Metals, Removal, Low Cost, Adsorbents.

Article Name:

Novel ZnTi LDH/h-BN nano composite for removal of two different organic contaminants: simultaneous visible light photo degradation of Amaranth and Diazepam.

Abstract: 

In the present study, a novel heterostructure nanocomposite consisting of hexagonal boron nitride (h-BN) and ZnTi layered double hydroxide was synthesized to remove two organic pollutants simultaneously from the aqueous solution under visible light irradiation at room temperature. ZnTi LDH/h-BN represents a cost-effective reusable material that showed both adsorption and substantial photocatalytic performance in the degradation of amaranth (AM) azo dye and diazepam (DZP) as organic contaminants of water. Various analyses were performed to assess the morphology, characteristic features, and synthesis accuracy of the as-prepared materials that proved the proper formation of the nanocomposite. Additionally, an acceptable reduction was observed in the bandgap of the nanocomposite in comparison with the bandgap of ZnTi LDH. Furthermore, the effect of various parameters, including pH of the solution, contaminant concentration, and catalyst dosage, were studied on the adsorption and photocatalytic activity to find out optimum conditions during the process. Results revealed that the synthesized catalysts had performed exceptionally well in adsorbing and degrading considered pollutants even in removing both from the same solution. The layered structure of the h-BN played a crucial role in providing an available surface area needed for adsorption and better dispersion of the photocatalyst particles, and at the same time, ZnTi LDH reduced AM and DZP by its photocatalytic activity. In the optimal conditions, the simultaneous removal efficiency of the molecule of AM and DZP was measured to be more than 99% and 95%, respectively.

Reference:

Omrani, E., Ahmadpour, A., Heravi, M., & Bastami, T. R. (2022). Novel ZnTi LDH/h-BN nanocomposites for removal of two different organic contaminants: Simultaneous visible light photodegradation of Amaranth and Diazepam. Journal of Water Process Engineering, 47, 102581.

Keywords:
Nanocomposite, Removal, Organic Contaminant, Amarenth, Diazepam.

Article Name:

Synthesis and characterization of magnetic poly (acrylonitrile-coacrylic acid) nanofibers for dispersive solid phase extraction and pre-concentration of malachite green from water sample.

Abstract: 

This research describes the development of a new design of nanosorbents, magnetic poly(acrylonitrile-co-acrylic acid) (PAN-co-AA) nanofibers, for the pre-concentration of malachite green (MG) residues in water samples via dispersive magnetic solid phase extraction (d-MSPE) technique. After pre-concentration, the spectrophotometric method was used to determine MG. Magnetic PAN-co-AA nonwoven nanofibers was fabricated by the optimized electrospinning technique after optimization of electrospinning conditions. According to the results, increasing magnetic nanoparticles (MNPs) into polymeric matrix led to significant reduction of fiber diameter from 360 to 70 nm. This change was associated with an increase in nanofibers surface area (from 9.66 m² g⁻¹ to 12.09 m² g⁻¹). Fabricated magnetic nanofibers demonstrated suitable magnetic properties (3.6 emu g⁻¹), so it can be used for magnetic separation and easy extraction techniques. In the following step, magnetic PAN-co-AA nanofibers (MNFs) were used to determine MG in aquatic samples. The influence of different parameters on extraction was investigated and optimized to improve the extraction efficiency of MG. The calibration curve was linear in the range of 0.3–1.8 mg L⁻¹ of MG with R² = 0.9911. The detection limit, based on three times the standard deviation of the blank, was 0.03 mg L⁻¹. The relative standard deviation (RSD) for 1, 1.5 and 1.8 mg L⁻¹ of MG was 4.31%, 6.86% and 7.68% (n = 6), respectively. MG was analyzed in different water samples (urban, mineral and river waters) using the proposed method. The recoveries were 95.83–103.3% with an RSD of less than 8%. The results showed that MNFs were suitable for pre-concentration and determination of trace amount of MG in wastewater samples.

Reference:

Sabzroo, N., Bastami, T. R., Karimi, M., Heidari, T., Agarwal, S., & Gupta, V. K. (2018). Synthesis and characterization of magnetic poly (acrylonitrile-co-acrylic acid) nanofibers for dispersive solid phase extraction and pre-concentration of malachite green from water samples. Journal of industrial and engineering chemistry, 60, 237-249.

Keywords:
Nanoparticles, Synthesis ,Characterization, Nanofiber, Extraction