Arsenic removal from drinking water using low-pressure nanofiltration under various operating conditions

Abstract

Currently, one of the main environmental concerns is the toxicity caused by arsenic. Arsenic-polluted water can cause many human health problems including various cancerous diseases. In natural water, inorganic arsenic can be found in the forms of arsenite and arsenate, which have been found in several Iranian provinces – e.g., East Azerbaijan, Kurdistan, and the city of Bijar – in high concentrations. Modern nanofiltration (NF) technology enables a wide range of water resource pollutants to be controlled efficiently. In this study, in an attempt to enhance arsenic removal (both arsenite and arsenate) from drinking water using low pressure NF, operating conditions like arsenic concentration, the trans-membrane pressure applied, and a range of different temperatures have all been considered. The highest arsenate removal achieved was 94% with an initial concentration of 500 μg/L, at 7 bar pressure, and 28 °C. The highest arsenite removal was 90%, with an initial concentration of 100 μg/L, at 5 bar pressure, and also at 28 °C. Increasing the pressure had a positive effect on the removal of both species, however, increasing the temperature had negative impacts. It was always found that arsenate removal was better than arsenite removal.

Nanofiltration for Arsenic Removal: Challenges, Recent Developments, and Perspectives

“…The tailored membrane showed enhanced flux and rejection of As V because of the higher hydrophilicity of the membrane [ 167 ] [see Table 4 , TFN-0.05]. A similar TFN-NF membrane was also prepared where the doping particle used was water stable zirconium metal-organic framework (MOF) UiO-66 nanoparticles with different diameters, e.g., 30, 100, and 500 nm [ 160 ]. The TFN membrane comprising 30 nm UiO-66 exhibited the best performance among the three TFN-NF membranes.…”

“…The trend of arsenic removal with the change of temperature is not the same for all membranes as the applied pressure, such as increasing by 20 °C in temperature, the arsenate removal decreases 1.3% for NF-90 membrane, but 1.7% for NF-200 [ 219 ]. Besides this, the changing trend of arsenate and arsenite removal is the same, as a 5% decrease in the removal efficiency for both in the case of NF90-4040 with the increase of 9 °C temperature [ 160 ].…”

“…The tailored membrane showed enhanced flux and rejection of As V because of the higher hydrophilicity of the membrane [167] [see Table 4, TFN-0.05]. A similar TFN-NF membrane was also prepared where the doping particle used was water stable zirconium metal-organic framework (MOF) UiO-66 nanoparticles with different diameters, e.g., 30, 100, and 500 nm [160]. The TFN membrane comprising 30 nm UiO-66 exhibited the best performance among the three TFN-NF [163,164,[166][167][168]); TFN-Na-CQD-sodium ion modified carbon quantum dot (Na-CQD) incorporated thin-film nanocomposite (TFN) membranes with Na-CQD loadings of 0.05 wt% (adapted with permission from [163,164,[166][167][168]); TFN-MOF-thin-film nanocomposite membranes modified with water stable zirconium metal-organic framework (MOF) UiO-66 nanoparticles with diameters of 30 nm (adapted with permission from [163,164,[166][167][168]).…”

Model Fuel Deep Desulfurization Using Modified 3D Graphenic Adsorbents: Isotherm, Kinetic, and Thermodynamic Study

“…Some cancerous heavy metals such as arsenic can be removed from water by means of modified forms of GO. 34,35 have been used in the reverse osmosis (RO) desalination process to control biofouling, which is a common problem in RO plants. 36,37 Hummers' method is a common approach to make GO, which can be reduced to form graphene or partially reduced graphene oxide (rGO).…”

“…Graphene, graphene oxide (GO), and their derivatives have been used as adsorbents, catalysts, and membranes for environmental purposes. Some cancerous heavy metals such as arsenic can be removed from water by means of modified forms of GO. , Graphene derivatives have been used in the reverse osmosis (RO) desalination process to control biofouling, which is a common problem in RO plants. , Hummers’ method is a common approach to make GO, which can be reduced to form graphene or partially reduced graphene oxide (rGO). There are various methods for reduction of GO that differ in preparation conditions and final graphene structures and properties .…”