The formation and distribution of haloacetic acids in copper pipe during chlorination

Abstract

The formation and distribution of HAAs in copper pipe during chlorination was investigated. To determine the material influence of copper pipe, parallel experiments were performed in glass pipe. Results showed that there was no obvious difference between the sum of haloacetic acids (HAAs) and trihalomethanes (THMs) produced in copper pipe compared to that produced in glass pipe over a 12 h period. However, significant differences were observed about the distribution of five haloacetic acids in copper pipe and in glass pipe. Relatively less trichloroacetic acid (TCAA) and more monochloroacetic acid (MCAA), dichloroacetic acid (DCAA), dibromoacetic acid (DBAA) and trihalomethanes (THMs) were produced in copper pipe than those in glass pipe. Corrosion scale on the wall of copper pipe was analyzed using X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM) and energy dispersive spectroscopy (EDS). The results showed the scales on the pipe surface mainly consisted of Cu 2 O, CuO and Cu (OH) 2 or CuCO 3 . During 24 h stagnation, copper released gradually from copper pipe. The influences of copper (II) and copper oxides on the distribution of HAAs were investigated in designed experiments. Results showed that less amount of TCAA, more amounts of DCAA and MCAA were formed with increasing concentration of copper (II). It was because the accelerative effect of copper (II) on the depletion of chlorination restricted the formation of TCAA precursor and the further formation of TCAA. Owing to the transformation of DCAA precursor to TCAA precursor was limited, more DCAA precursor could yield DCAA. The influences of Cu 2 O and CuO on the distribution of TCAA and DCAA were the result of copper released at higher content.

Formation of Bromate and Halogenated Disinfection Byproducts during Chlorination of Bromide-Containing Waters in the Presence of Dissolved Organic Matter and CuO

“…[20][21][22][23] This disproportionation 62 pathway led to elevated BrO 3 − concentrations (e.g., 50 µg L -1 ) exceeding the maximum 63 contaminant level (i.e., MCL, 10 µg L -1 regulated by US EPA 12 ) during chlorination of bromide-64 containing waters in distribution systems. 24 In addition, previous studies showed that CuO can 65 enhance HOCl/HOBr reactions with iodate to periodate and activate the reactivity of the other 66 halogen-containing oxidant (e.g, ClO 2 ).…”

Co-occurrence profiles of trace elements in potable water systems: a case study

“…For example, arsenic is found primarily in mobilization-resistant fraction followed by crystalline Fe oxide-bound and amorphous mineral colloid-bound forms in corrosion scales and deposits found in water distribution systems (Peng and Korshin 2011). Not only Fe, but also Cu (II) release from copper oxides exhibit similar reactions in the formation of haloacetic acids such as monochloro and dichloroacetic acid (Li et al 2008). These, thereby, may influence release and mobilization reactions of toxic trace elements from Cu pipe scales and corrosion products into drinking water.…”

Effect of zinc on the transformation of haloacetic acids (HAAs) in drinking water

“…On the other hand, DBPs may be translated via hydrolysis, biological transformation, and abiotic reduction to a variety of degradation products [10,11]. Also they may be sorbed at or react within the pipe surface [12,13]. Thus, pipe surface is a crucial gist affecting all of the processes above.…”