Arsenic Removal via Cellulose-Based Organic/Inorganic Hybrid Materials from Drinking Water

Abstract

Cellulose/silica derived hybrids materials (CSH), functionalized with aluminium, calcium, and propylammonium ions, were tested for their possible use in the removal of arsenic from aqueous solutions with controlled compositions to levels lower than 10 μg As/L. CSH were synthesized by sol-gel method using bleached pulp, as source of cellulose fiber, and tetraethoxysilane (TEOS) as main silica precursor. The silica network, made in situ, contained various anchored cations such as propylammonium (CSH-PA), aluminium (CSH-Al) and, calcium (CSH-Ca). Thin films or mesoparticles of silica were deposited on cellulose fibers as shown by SEM and XRD. These hybrid materials were immersed in controlled ionic strength aqueous solutions with arsenic concentrations lower than 0.2 mg As/L. The best performance was shown by CSH-PA that was able to remove a maximum of 20 % of the total arsenic concentration.

Arsenic contamination of groundwater sources and a comparative study of its remediation by various conventional and recent approaches in Nepal

“…It can only remove 20% of the arsenic. As a result, it is only appropriate for use in areas where arsenic concentrations are slightly higher than 10 ppb 10 …”

“…Many minerals, including marble, hydrothermal veins, sulfide veins, and calcareous shales, naturally contain arsenic combined with sulfur and other metals 9 . So, it can be found in unused mineral excavation sites from the past, where soils and water sources have accumulated 10 . The aerial oxidation of pyrite material lowers the pH of the groundwater and facilitates the hydrolysis of ferric arsenate and ferric arsenite, which are the most common alternation products of arsenopyrite 11 .…”

“…It was discovered that elevated arsenic levels in drinking water appear to be very common in various places in the Andes Mountains 15,16 . So, the majority of arsenic contamination of groundwater is geogenic 10 . While the burning of fossil fuels is one of the most damaging human activities, using pesticides, and so on can also cause arsenic pollution 17 .…”

“…9 So, it can be found in unused mineral excavation sites from the past, where soils and water sources have accumulated. 10 The aerial oxidation of pyrite material lowers the pH of the groundwater and facilitates the hydrolysis of ferric arsenate and ferric arsenite, which are the most common alternation products of arsenopyrite. 11 Arsenic accumulates downstream due to the weathering of Himalayan sediments during erosion and transit.…”

“…15,16 So, the majority of arsenic contamination of groundwater is geogenic. 10 While the burning of fossil fuels is one of the most damaging human activities, using pesticides, and so on can also cause arsenic pollution. 17 Besides, the excessive withdrawal of groundwater for irrigation in the agricultural field and other activities is also the cause of arsenic contamination in groundwater.…”