Sorption of heavy metals from aqueous solution by dehydrated powders of aquatic plants

Abstract

Ruppia maritima and Echinodorus amazonicus were prepared in a dehydrated powder form. The characteristics and mechanisms of adsorption of heavy metals were studied under various pH values, reaction times, and heavy metal ion concentrations. The results showed that under different pH and reaction time conditions, heavy metal adsorption was leadThe adsorption of lead increased linearly with the lead concentration. For cadmium, zinc and copper, the adsorption was saturated when metal ion concentration exceeded 200 mg/L. When a Freundlich model was applied, R 2 values for the heavy metal adsorption by the aquatic plants mostly exceeded 0.9. The adsorption of heavy metal ions by these two aquatic plant powders was better explained by the Lagergren second-order equation than the first-order equation. From the Fourier Transform Infrared spectra, there was an adsorption peak at 2,115 cm -1 for R. maritima. The peak shape did not change with metal affiliation except there was a shift of peak wavelength before adsorption. The results indicate that the mechanism of heavy metal adsorption by the two species is not simply on the mono-molecular layer level, and that intra-particulate dispersal is the dominant process. Heavy metal pollution does not affect the basic chemical components, and major substances involved in heavy metal adsorption including carbohydrates, cell wall pectin, and protein functional groups.

Phosphorylated nanocellulose papers for copper adsorption from aqueous solutions

“…hydroxide, sulphide or chelating precipitation, as well as ion-exchange or adsorption (Wan Ngah et al 2002;Akar et al 2009;Zhu and Li 2015;Jain et al 2016), e.g. with activated carbon, carbon nanotubes, magnetic nanoparticles (Feitoza et al 2014), low-cost adsorbents from industrial waste streams (Castaldi et al 2015;Cretescu et al 2015) or bioadsorbents (Davis et al 2003;Deng et al 2013;Hokkanen et al 2013;Shaheen et al 2013;Bansal et al 2014;Ş en et al 2015;Komkiene and Baltrenaite 2016). Furthermore, membrane filtration processes (Ujang and Anderson 1996;Qdais and Moussa 2004) such as ultrafiltration, nanofiltration, reverse osmosis or electrodialysis are utilized.…”

Batch Removal of Aqueous Nitrate Ions Using an Effective Nano-Biocomposite

“…FTIR spectra were recorded in the transmission mode between 500 and 4000 cm -1 for all samples (Figure 3). cellulose (Amir et al, 2004), (4) 1410-1450 cm -1 represented the C-O stretching vibration in carboxylate ions (-COO-), (5) 1450-1480, 2850, and 2920 cm -1 represented the symmetric and asymmetric stretching vibration of the CH 2 and CH 3 , (6) 1510-1530 cm -1 associated to the presence of N-H and C-H bending and stretching vibration (amide II region), (7) the amide I peak appeared at 1610-1650 cm -1 (Deng et al, 2013), (8) 1734 cm -1 assigned to the C=O stretching vibration, and (9) 3000-3800 cm -1 attributed to the presence of -OH and -NH stretching vibration of carbohydrate, cell wall compounds, and proteins. The spectrum of PCAC (Figure 3c) reveals bands centered at 700-900 cm -1 attributed to the aromatic C-H stretching vibration.…”

Preparation and characterization of a novel electrospun ammonium molybdophosphate/polyacrylonitrile nanofiber adsorbent for cesium removal

“…Various technologies have been investigated for the removal of toxic metals from industrial wastewater such as thermal treatment, precipitation, reverse osmosis, membrane filtration, solvent extraction, biological treatment and inorganic and organic ion exchange processes [8][9][10]. Most of these methods are limited by technical, economic, environmental and health problems that correspond to low efficiency, long-time of processing and high-energy consumption.…”