Arsenic removal from groundwater using iron electrocoagulation: Effect of charge dosage rate

Abstract

We demonstrate that electrocoagulation (EC) using iron electrodes can reduce arsenic below 10 µg/L in synthetic Bangladesh groundwater and in real groundwater from Bangladesh and Cambodia while investigating the effect of operating parameters that are often overlooked, such as charge dosage rate. We measure arsenic removal performance over a larger range of current density than in any other single previous EC study (5000 fold: 0.02 -100 mA/cm 2 ) and over a wide range of charge dosage rates (0.

Evaluation of a Point-of-Use Electrocoagulation System for Arsenic Removal

“…The cumulative charge dosage needed to produce sub-10 µg/L soluble arsenic levels increased from about 175 C/L for the system employing the smaller plates to over 220 C/L for the system using the larger plates. These trends are consistent with results reported by others 15 . The higher current draw associated with the larger plates, together with the lower electrical efficiency of the associated EC module, led to a decision to eliminate use of the 15 cm x 15 cm plates from further consideration where limitations associated a rechargeable battery power source dictated use of the more efficient system.…”

“…In accordance with the results of others 15,16 , the goal during this test cycle was to identify a module configuration that would provide (a) a batch reaction cycle time of less than 60 minutes, (b) a charge dosage rate of no more than 6 coulombs per liter per minute (C/L/min), (c) a cumulative charge dosage of no more than 180 coulombs per liter (C/L) for an initial 300 μg/L arsenic concentration, and (d) dimensional compatibility with the chosen EC reactor vessel. A number of test runs were terminated early when it became apparent that the tested plate spacing would not be able to provide satisfactory operation.…”

“…Experimentation revolved around treating the type of arsenic-contaminated groundwaters commonly encountered in South Asia where arsenic levels range between 100 and 300 µg/L. EC-based treatment was chosen because of its potential to produce a high-quality treated water in a relatively simple, resource-frugal manner 12,15 . Because the prototype system was designed for application in the rural areas of developing nations, relevant design and operating constraints were identified through communications with the head of a non-governmental agency (NGO) providing services in south Asia.…”

Arsenic Sorption Using Mixtures of Ion Exchange Resins Containing N-Methyl-D-Glucamine and Quaternary Ammonium Groups

“…The arsenic aqueous solutions were adjusted to a pH of 3-9 using dilute HNO 3 and NaOH solutions. In these studies, various amounts of PVBNMDG (10,20,30,40, and 50 mg) and PClVBTA (1, 2, 3, 4, 5, and 10 mg) were contacted with 10 mL As(V) solution (10 mg/L) in a shaker at 30 ºC under a stirring rate of 140 rpm for 24 hours. The sorption performances of these resins were investigated by changing the polymer:polymer ratio in mol.…”

“…Two forms of arsenic are common in natural waters: arsenite (AsO 3 3-) and arsenate (AsO 4 3-), referred to as arsenic (III) and arsenic (V), respectively 17,20,21 .…”