Arsenic and antimony in water and wastewater: overview of removal techniques with special reference to latest advances in adsorption

https://people.clas.ufl.edu/azimmer/files/Publication-pdf/Hu15_Batch-and-column-sorption-of-arsenic-onto-iron-impregnated-biochar.pdf

Batch and column sorption of arsenic onto iron-impregnated biochar synthesized through hydrolysis.

Naturally occurring diatomaceous earth (diatomite) has been tested as a potential sorbent for Pb(II) ions. The intrinsic exchange properties were further improved by modification with manganese oxides. Modified adsorbent (referred to as Mn-diatomite) showed a higher tendency for adsorbing lead ions from solution at pH 4. The high performance exhibited by Mn-diatomite was attributed to increased surface area and higher negative surface charge after modification. Scanning electron microscope pictures revealed a birnessite structure of manganese oxides, which was featured by a plate-like-crystal structure. Diatomite filtration quality was improved after modification by manganese oxides. Good filtration qualities combined with high exchange capacity emphasised the potential use of Mn-diatomite in filtration systems.

19. Al-Degs Y., MAM Khraisheh, Tutunji, M.F, Sorption of lead ions on diatomite and manganese-oxides modified diatomite.

Iron oxide and its modified forms as an adsorbent for arsenic removal: A comprehensive recent advancement

Nanotechnology has great potential to improve water purification and decontamination efficiency. Nanomaterials are efficient at removing organic and inorganic pollutants and heavy metals from wastewater and killing microorganisms. The distinctive characteristics of metal oxides make them the most varied class of materials, and they have properties that cover almost all aspects of solid-state physics and material science. Only a few review articles in the literature specifically address metal oxide nanoparticles and their application in the treatment of wastewater. This review article aims to fill this gap and present a thorough review of the various types of metal oxide nanoparticles in contaminating water impurities. Metal oxide nanoparticles have great potential for treating contaminated water due to their unique properties, such as their large surface areas and low concentration. This paper discussed in detail five metal oxide nanoparticles and their applications for antibacterial and wastewater applications. Highlights •In literature, only a few review articles addresses applications of metal oxide nanoparticlesin the treatment of wastewater.•We present a thorough review of the various types of metal oxide nanoparticles in contaminating water impurities.•Metal oxide nanoparticles have great potential for treating contaminated water.•This paper discussed five metal oxide nanoparticles and their applications for antibacterial and wastewater applications.

The role of some important metal oxide nanoparticles for wastewater and antibacterial applications: A review

The present work deals with a simple in situ soft chemical synthesis of nanoscale copper(II) oxide, together with its characterization and a study of the adsorption and desorption behaviors of Pb(II) on nanoscale CuO. The nanoparticles are characterized by XRD, FESEM, TEM and BET surface area analyses. Electron microscopy clearly reveals a rod-like morphology of rhombohedral CuO, with an average diameter of ∼5 nm and a length extending up to 50 nm. BET shows the average surface area of the nanorods to be ∼52.57 m2 g−1. In an adsorption study, the influence of operational conditions, such as the contact time, the initial concentration of Pb(II), the initial pH of the solution and the temperature, on the adsorption of Pb(II) has also been examined. Studies also reveal that the uptake of Pb(II) onto CuO is a fast process; >70% of the uptake occurred within the first 10 min of contact time and uptake reached >92% within 60 min. The maximum sorption capacity of Pb(II) is 3.31 mg g−1 at 298 K. The +ve ΔS° value and the +ve ΔH° value of 37.77 kJ mol−1 indicate the endothermic nature of the adsorption process, whereas a decrease of Gibbs free energy (ΔG°) with increasing temperature indicates the spontaneous nature of the adsorption process. The adsorbent can be up to 84.1% regenerated using dilute acid and shows potential for the removal of lead from contaminated water.

CuO nanorods: a potential and efficient adsorbent in water purification

Nano-sized magnesium oxide (nano-MgO) was investigated for adsorption of fluoride from water. The pure and fluoride adsorbed nano-MgO were characterised by Brunauer–Emmett–Teller, high resolution transmission electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy and energy dispersive X-ray analyses. The surface area of the adsorbent was found to be 92.46 m2/g. Maximum (90%) fluoride removal was obtained with 0.6 g/L dosage of nano-MgO. Fluoride adsorption by nano-MgO was found to be less sensitive to pH variations. Fluoride sorption was mainly influenced by the presence of OH− ion. The presence of other ions studied did not affect the fluoride adsorption capacity of nano-MgO significantly. It has been observed that Freundlich model was better fitted as compared to Langmuir model which indicated the multilayer adsorption of the adsorbent following a pseudo-second order kinetics. Regeneration study showed that 1 M HCl was the best eluent with 95% desor...

https://www.tandfonline.com/doi/pdf/10.1080/17458080.2012.675522

Defluoridation of water using nano-magnesium oxide

A novel and facile method for the synthesis of uniform stoichiometric powder form of non-magnetic iron oxide-hydroxide nanoparticles with spherical morphology and its application for defluoridation of drinking water is reported. X-ray powder diffraction analysis (XRD), BET surface area, FTIR, field emission scanning electron microscopy (FESEM) and Transmission electron microscopy (TEM) images were used to characterize nanoscale iron oxide-hydroxide. Transmission electron microscopy (TEM) image revealed the formation of iron oxide-hydroxide nanoparticles with spherical morphology. The iron oxide-hydroxide nanoparticles showed an excellent ability to remove fluoride (F − from contaminated water over a wide range of pH. The influences of temperature, stirring speed, pH, adsorbent dose and contact time were studied. The equilibrium data were tested with various isotherm models and finally, a calculation procedure was reported for the calculation of adsorbent requirement. The fluoride adsorbed nanoparticles was regenerated upto 70% using sodium hydroxide or hydrochloric acid solution. The iron oxide-hydroxide nanoparticles can be used as an effective and replicable adsorbent media for defluoridation of water in presence of competing anions like chloride, iodate, iodide and sulphate.

Removal of fluoride from water using iron oxide-hydroxide nanoparticles.

A method for removal of iron and arsenic (III) from contaminated water using iron oxide-coated sand and limestone has been developed for drinking water. For the intended use, sand was coated with ferric chloride and used as filtering media. Limestone was added onto the coated sand and the effect of limestone addition on removal efficiency of iron and arsenic was monitored. Both batch and column experiments were conducted to investigate the efficiency of coated sand and limestone as filtering media. Maximum removal of iron (99.8 %) was obtained with coated sand at a dose of 5 g/100 ml and by adding 0.2 g/100 ml of limestone at pH 7.3. Arsenic (III) removal efficiency increased with the increased dose of coated sand and was best removed at pH 7.12. The maximum adsorption capacity for arsenic (III) obtained from Langmuir model was found to be 0.075 mg/g and the kinetics data followed pseudo-first order better than pseudo-second order. Energy dispersive X-ray analysis and FT-IR study proved the removal of iron and arsenic. Column experiment showed removal of iron and arsenic (III) to <0.3 mg/l and 10 μg/l, respectively, from an initial concentration of 20 mg/l (iron) and 200 μg/l (arsenic).

/pdf/removal-of-iron-and-arsenic-iii-from-drinking-water-using-5cuz6qybi8.pdf

Iohborlang M. Umlong

Papers

CuO nanorods: a potential and efficient adsorbent in water purification

Defluoridation of water using nano-magnesium oxide

Removal of fluoride from water using iron oxide-hydroxide nanoparticles.

Removal of iron and arsenic (III) from drinking water using iron oxide-coated sand and limestone

Iron oxide hydroxide nanoflower assisted removal of arsenic from water