Efficient removal of uranium(VI) from aqueous medium using ceria nanocrystals: an adsorption behavioural study

Nam

2021

IJERPH

In the present study we investigated the ability of the microalgal strain Parachlorella sp. AA1 to biologically uptake a radionuclide waste material. Batch experiments were conducted to investigate the biosorption of uranyl ions (U(VI)) in the 0.5–50.0 mg/L concentration range by strain AA1. The results showed that AA1 biomass could uptake U(VI). The highest removal efficiency and biosorption capacity (95.6%) occurred within 60 h at an initial U(VI) concentration of 20 mg/L. The optimum pH for biosorption was 9.0 at a temperature of 25 °C. X-ray absorption near edge structure analysis confirmed the presence of U(VI) in pellets of Parachlorella sp. AA1 cells. The biosorption methods investigated here may be useful in the treatment and disposal of nuclides and heavy metals in diverse wastewaters.

Section: Resultsmentioning

confidence: 99%

Biosorption of Uranyl Ions from Aqueous Solution by Parachlorella sp. AA1

Nam

2021

IJERPH

“…To examine the effect of adsorbent dosage on the Mn 2+ removal, adsorption experiments were set up with various amounts of GVR from 4g/L to 20g/L. The removal efficiency of GVR increased with increasing adsorbent amount which is due to the increase of the number of vacant adsorption sites and the greater available surface area of 3 m 2 /g (Alemayehu et al, 2017) favoring increased Mn 2+ adsorption (Kuncham, Nair, Durani, & Bose, 2017).…”

Section: Effect Of Adsorbent Dosagementioning

confidence: 99%

Adsorptive Removal of Manganese from Water Intended for Consumption by Use of Cost-effective Gisenyi Volcanic Rocks

Muhire

Itete

2021

Preprint

This study determined the capacity of Gisenyi volcanic rocks (GVR) located in Rwanda (Nothern Province) to remove manganese from groundwater. Various experimental conditions such as adsorbent dosage and contact time were investigated. The dosage of GVR has shown to be a highly influencing factor in manganese removal from groundwater. The adsorption proceeded via a fast initial metal removal followed by a slow uptake during the first 6 h and equilibrium after 24 h. For the initial manganese concentration of 1.5 mg/L, the removal efficiency varied from 42.5–72.9% for 4g/l and 20g/l of VGR dosage respectively. The Freundlich and Languimur isotherm constants indicated that the adsorption of Mn2+ on GVR is a physical process and favorable. The pseudo-first-order and pseudo-second-order kinetic models also show that the adsorption of Mn2+ onto GVR is a physical process.

“…Solution pH is an important parameter that affects biosorption. The species of uranium ion that exists in solution and the surface charge of microbes are both pH dependent [37]. The effect of pH on the biosorption of U(VI) was performed at pH 1.00-7.00 and the results are shown in Fig.…”

Section: Effect Of Initial Ph On the Biosorption Of U(vi)mentioning

confidence: 99%

Reduction and Enrichment of Uranium after Biosorption on Inactivated <i>Saccharomyces cerevisiae</i>

Zhang¹,

Dong²,

Liu³

et al. 2020

Pol. J. Environ. Stud.

Microorganisms not only have a strong biosorption capacity but also can achieve tremendous volume reduction effects for radionuclide wastes. Batch experiments were conducted to investigate the biosorption characteristics of uranium on inactivated Saccharomyces cerevisiae and the volume reduction and enrichment of uranium after biosorption were also studied in combination with the ashing method. The results revealed that inactivated S. cerevisiae biomass was able to adsorb uranium. The maximum removal efficiency and biosorption capacity for uranium were 96.8% and 31.8 mg/g, respectively. The optimum pH for U(VI) removal was 2.75 and U(VI) biosorption was well described by the Freundlich isotherm model. Thermodynamic investigations showed that biosorption of U(VI) on inactivated S. cerevisiae was a spontaneous and endothermic process. In the kinetic studies, U(VI) adsorption on inactivated S. cerevisiae reached an equilibrium in 60 min and followed a pseudo-secondorder kinetics model. The 100 mg/L of uranium was reduced to less than 0.05 mg/L after 6 rounds gradient descent adsorption, which was enough to meet the National uranium wastewater discharge standards. The ashing experiment demonstrated that ashing process resulted in a large volume and weight reduction ratio as well as enrichment for uranium in the ash. XRD results showed that the species of uranium that existed in the ash were uranium phosphate and KPUO 6 •3H 2 O. Waste volume reduction and metal enrichment can be obtained by ashing treatment of the biological absorbent. The method may be beneficial for nuclide and heavy metal disposal treatment in many fields.