Anion exchange pretreatment for the removal of natural organic matter from humic rich water

2011 ◽  
Vol 11 (6) ◽  
pp. 699-710 ◽  
Author(s):  
M. Molczan ◽  
M. Szlachta

The treatment of humic rich water using anion exchange, coagulation and PAC-adsorption was studied, both independently and in sequence in that order. The commercial aluminium-based coagulant PAX-16, powdered activated carbon W35 and the magnetic ion exchange resin (MIEX®) were used in the study. The source of humic substances was natural water (25.0 g C/m3 as DOC) flowing out from the Great Batorow Peat-Bog (Lower Silesia, Poland). In addition to DOC, color, UV254 absorbance, specific UV absorbance (SUVA254), turbidity, pH and alkalinity were also analyzed. Regardless of the applied technology, in the phase of raw water treatment extraordinary solutions were necessary to treat the humic rich water – a high coagulant (13.1 g Al/m3) or PAC (>200 mg/dm3) dose or a low bed volume (200 BVs) in the case of anion exchange. MIEX®DOC pretreatment had a very positive influence on the course and effects of coagulation resulting in a higher coagulant efficiency for removing organic compounds. In this respect, MIEX®DOC pretreatment allowed the application of a required coagulant dose four times lower compared to the coagulation of raw water. In testing the sequence of processes (MIEX®DOC – coagulation – PAC-adsorption), coagulation was the main process responsible for reducing the SUVA254 value. The improvement in water quality after PAC-adsorption was not significant, although the process removed DOC fractions that could not be removed by coagulation. Each of the applied methods played a role in the treatment of humic rich water and the nearly complete removal of NOM was achieved (in the sequence of processes) under relatively rational operating conditions for the treatment techniques.

2013 ◽  
Vol 361-363 ◽  
pp. 801-804
Author(s):  
Jian Wei Ma ◽  
Ya Rui Song

The objective of this research was to compare enhanced coagulation with anion exchange for removal of natural organic matter (NOM) and bromide. Treatment with a magnetic ion exchange resin (MIEX) was the primary focus of this study. The performance of the magnetic ion exchange resin,MIEX, in the treatment of raw water was investigated. MIEX can effectively remove UV-absorbing substances DOC. The removal of organic substances is accompanied by the elimination of other undesirable components, such as nitrogen and phosphorus. The optimal process parameters are at resin doses of 5-10 mL L1and contact time of 10-15 min, as determined via jartests. Based on this study, MIEX treatment is a suitable and efficient pretreatment method for the removal of extra dissolved organic matters and nitrates in raw water .


2009 ◽  
Vol 9 (2) ◽  
pp. 199-205 ◽  
Author(s):  
M. R. D. Mergen ◽  
B. J. Adams ◽  
G. M. Vero ◽  
T. A. Price ◽  
S. A. Parsons ◽  
...  

The aim of the research presented in this paper was to gain greater insight into the characteristics of NOM removed by MIEX® Resin. Previous studies have shown that MIEX® Resin increases the level of removable DOC when used in combination with coagulation, suggesting that these two processes target a different type of organics. Initially the characteristics of DOC in regenerant solutions from four different MIEX® Resin treatment plants were analysed and compared to DOC in the respective raw water. Following this the raw water and the regenerant solutions were coagulated and the characteristics of the residual DOC analysed and compared to the regenerant solutions prior to coagulation. From the regenerant solutions it was seen that MIEX® Resin targets DOC of increased UV254 absorbance, increased charge density and of mid to low molecular weight (5 to 2 kDa). In terms of hydrophobicity no preference of MIEX® Resin for a specific NOM type was seen. The presence of hydrophilic neutral acids in the regenerant solution was unexpected since the removal of only highly charged organic species was expected. Charge density measurements however revealed the presence of functional groups, allowing hydrophilic neutrals to be removed by anion exchange. Comparative coagulation of the raw water and regenerant solution showed that both a residual DOC of similar hydrophobicity in the sub 3 kDa area. Considering that this DOC fraction was present in the regenerant it was concluded that MIEX® Resin removes organics recalcitrant to coagulation from raw water and therefore increases DOC removal when both methods are combined.


2013 ◽  
Vol 13 (1) ◽  
pp. 123-129
Author(s):  
Zhizhen Xu ◽  
Ruyuan Jiao ◽  
Xiaomin Yan ◽  
Dongsheng Wang ◽  
Mary Drikas ◽  
...  

Dissolved organic matter (DOM) and bromide as principal precursors to halogenated disinfection byproducts (DBPs) have potential risks on the safety of drinking water after disinfection. Removal of DOM and bromide in raw water from two different waterworks using magnetic ion exchange resin (MIEX), ferric coagulation and their combination was investigated. Results showed that as MIEX dose increased, DOM and bromide coexisting in raw water could be removed effectively. DOM tended to be mainly removed by MIEX at low dose (<4 mL/L), regardless of the bromide concentration. Bromide could compete for exchange sites with DOM at high MIEX dosage (>4 mL/L). The fluorescence spectra and high performance size-exclusion chromatogram analysis indicated that at low MIEX dosage, bromide decreased the removal of low molecular weight (MW), soluble microbial byproduct-like and aromatic protein-like organic matters, which had lower affinity with MIEX in raw water. The removal of high MW humic acid, which presented greater affinity with MIEX, was not influenced at low MIEX dose but decreased at high MIEX dose with the addition of bromide. The combination of MIEX and ferric coagulation significantly enhanced the removal of DOM and reduced the requisite ferric dose by at least 67% compared to coagulation alone.


2013 ◽  
Vol 726-731 ◽  
pp. 3185-3188
Author(s):  
Jian Wei Ma ◽  
Ya Rui Song

The objective of this research was to compare enhanced coagulation with anion exchange for removal of natural organic matter (NOM) and bromide. Treatment with a magnetic ion exchange resin (MIEX) was the primary focus of this study. The performance of the magnetic ion exchange resin,MIEX, in the treatment of raw water was investigated. MIEX can effectively remove UV-absorbing substances DOC. The removal of organic substances is accompanied by the elimination of other undesirable components, such as nitrogen and phosphorus. The optimal process parameters are at resin doses of 5-10 mL L1and contact time of 10-15 min, as determined via jartests. Based on this study, MIEX treatment is a suitable and efficient pretreatment method for the removal of extra dissolved organic matters and nitrates in raw water .


2012 ◽  
Vol 12 (6) ◽  
pp. 878-887 ◽  
Author(s):  
L. Verdickt ◽  
W. Closset ◽  
V. D'Haeseleer ◽  
J. Cromphout

The raw water of water treatment works ‘the Blankaart’ (Belgium) is characterized by high levels of NOM (Natural Organic Matter), alkalinity and sulfate. From 2006 until present, the possibility of applying fluidized ion exchange for NOM removal has been investigated at the plant. Pilot testing using Miex® (Magnetic Ion Exchange) resin demonstrated that under standard operating conditions, a TOC (Total Organic Carbon) removal efficiency of 40 to 50% can be achieved. Moreover, jar tests demonstrated that the application of ion exchange as a pretreatment for enhanced coagulation would allow the coagulant dose to be reduced by 60% without compromising effluent quality. Finally, column experiments were conducted to evaluate (i) the effect of full brine reuse and (ii) the possibility of using less expensive conventional ion exchange resins instead of the patented Miex® resin. Recuperation of the waste brine after flocculation with a ferric salt and dewatering was found to have no significant impact on the NOM removal efficiency. Column experiments with Miex® and conventional type 1 anion exchange resins revealed that the fluidization characteristics of both types of resin allow use in fluidized bed systems and that with both types of resin, similar NOM removal efficiencies can be attained. However, higher contact times are required when conventional resins are applied.


2021 ◽  
Vol 5 (1) ◽  
Author(s):  
Daire Tyndall ◽  
Sonia Jaskaniec ◽  
Brian Shortall ◽  
Ahin Roy ◽  
Lee Gannon ◽  
...  

AbstractNickel–iron-layered double hydroxide (NiFe LDH) platelets with high morphological regularity and submicrometre lateral dimensions were synthesized using a homogeneous precipitation technique for highly efficient catalysis of the oxygen evolution reaction (OER). Considering edge sites are the point of activity, efforts were made to control platelet size within the synthesized dispersions. The goal is to controllably isolate and characterize size-reduced NiFe LDH particles. Synthetic approaches for size control of NiFe LDH platelets have not been transferable based on published work with other LDH materials and for that reason, we instead use postsynthetic treatment techniques to improve edge-site density. In the end, size-reduced NiFe LDH/single-wall carbon nanotube (SWCNT) composites allowed to further reduce the OER overpotential to 237 ± 7 mV (<L> = 0.16 ± 0.01 μm, 20 wt% SWCNT), which is one of the best values reported to date. This approach as well improved the long-term activity of the catalyst in operating conditions.


2008 ◽  
Vol 42 (8-9) ◽  
pp. 1977-1988 ◽  
Author(s):  
Max R.D. Mergen ◽  
Bruce Jefferson ◽  
Simon A. Parsons ◽  
Peter Jarvis

Energies ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1720
Author(s):  
Sabrina Campagna Zignani ◽  
Massimiliano Lo Faro ◽  
Stefano Trocino ◽  
Antonino Salvatore Aricò

NiFe electrodes are developed for the oxygen evolution reaction (OER) in an alkaline electrolyser based on an anion exchange membrane (AEM) separator and fed with diluted KOH solution as supporting electrolyte. This study reports on the electrochemical behaviour of two different NiFe-oxide compositions (i.e., Ni1Fe1-oxide and Ni1Fe2-oxide) prepared by the oxalate method. These catalysts are assessed for single-cell operation in an MEA including a Sustainion™ anion-exchange membrane. The electrochemical polarization shows a current density of 650 mA cm−2 at 2 V and 50 °C for the Ni1Fe1 anode composition. A durability test of 500 h is carried out using potential cycling as an accelerated stress-test. This shows a decrease in current density of 150 mA cm−2 mainly during the first 400 h. The performance achieved for the anion-exchange membrane electrolyser single-cell based on the NiFeOx catalyst appears promising. However, further improvements are required to enhance the stability under these operating conditions.


2008 ◽  
Vol 57 (1) ◽  
pp. 57-64 ◽  
Author(s):  
B. Sani ◽  
E. Basile ◽  
C. Lubello ◽  
L. Rossi

A new Magnetic Ion EXchange resin for DOC (Dissolved Organic Carbon) removal (MIEX®DOC Resin) has been evaluated as water pre-treatment at the Drinking Water Treatment Plant (DWTP) of Florence in order to reduce the oxidant demand and disinfection by-products (DBPs) formation potential. This pre-treatment leads to several effects on downstream treatment processes. In this experimental study the effects of MIEX® pre-treatment on clariflocculation process were evaluated with respect to coagulant demand reduction and characteristics of flocs formed. The analysis was conducted using traditional jar test procedures and a Photometric Dispersion Analyser (PDA2000) which provided continuous information about the aggregation state of particles during the jar tests. For a fixed turbidity goal in clarified water, ion exchange pre-treatment led to coagulant dosage reduction up to 60% and PDA results shown that flocs formed in pre-treated water were bigger and more resistant to shearing effects than those formed by conventional clariflocculation.


Sign in / Sign up

Export Citation Format

Share Document