Abstract
BackgroundThe presence of iron (Fe) and manganese (Mn) ions in rocky beds leads to groundwater pollution. Moreover, their excessive concentration causes bad taste and color stains of water.MethodsTea leaves-derived char (TLC), rice straw-derived char (RSC), and nanosilica (NS) were used to adsorb Fe and Mn ions from water sources. The effects of parameters such as contact time, composition percentage, and particle size of biosorbents in a fixed-bed adsorption column were investigated.ResultsThe study on the adsorption of Fe and Mn ions showed that the amount of adsorption increased significantly by decreasing the particle size. Furthermore, the combination of nano-biosorbents with nanosilica improved the adsorption. The Thomas and Adams–Bohart models adequately indicated the adsorption of Fe and Mn ions onto nano-biosorbents in the column mode. The TLC and RSC with NS are applicable for the removal of Fe and Mn ions from groundwater.ConclusionsAccording to the BET analysis results, with more crushing of biosorbents by ball mill and placing them in the furnace, specific surface area of tea leaves and rice straw increased from 0.29 to 3.45 and from 3.70 to 10.99 m2/g, respectively. The absorption of iron and manganese from the aqueous solution increased with the percentage of nano-silica. According to breakthrough curves, under best conditions (the seventh mode), nano-biosorbents could remove 98.05% and 97.92% of iron and manganese ions, respectively. The maximum equilibrium capacity of the adsorption column (mg/g) was 256.56 for iron and 244.79 for manganese.Graphical abstract
Highlights
Iron and Manganese are two metals commonly found in wells water [1]
The removal of methylene blue from water by tea waste active with H3PO4 (H-AC), KOH (K-AC) and ZnCl2 (Z-AC) agents has been studied by Toli et al energy dispersive X-ray (EDX), Fourier transforms infrared spectra (FTIR), FESEM, X-ray diffractometer (XRD) and TGA analyses were performed on the adsorbents; the results showed that the adsorption capacity of H-AC adsorbent for removal of methylene blue is higher than the others [11]
The removal of methylene blue from water by Modified nano-SiO2 by Bismuth and Iron has been studied by Salimi et al scanning electron microscopy (SEM), FTIR, XRD and TEM analyses were performed on the adsorbents; the XRD results showed that Nanosilica structure is amorphous [15]
Summary
Iron and Manganese are two metals commonly found in wells water [1]. This is due to the presence of a rocky bed in the groundwater, causing excessive metal taste and stains [2]. Many studies has been conducted on the removal of metal ions from drinking water sources using rice straw-derived char, tea leavesderived char and nanosilica; the superiority of modified adsorbents in the removal of disturbing ions in water has been proved [13, 15, 25,26,27,28,29,30] Various analyses such as X-ray diffractometer (XRD) [15, 31, 32], Fourier transforms infrared spectra (FTIR) [24, 33], scanning electron microscopy (SEM), the energy dispersive X-ray (EDX) [13,14,15] and Brunauer–Emmett–Teller (BET) [34, 35] were used to determine different indicators of adsorbents. Their excessive concentration causes bad taste and color stains of water
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