Combination of nano TiO2 photocatalytic oxidation with microfiltration (MF) for natural organic matter removal

2009 ◽  
Vol 9 (1) ◽  
pp. 31-37 ◽  
Author(s):  
Hongwei Bai ◽  
Xiwang Zhang ◽  
Jiahong Pan ◽  
Darren D Sun ◽  
Jiahui Shao
Keyword(s):  
Organic Matter ◽  
Humic Acid ◽  
Natural Organic Matter ◽  
Removal Efficiency ◽  
Photocatalytic Oxidation ◽  
Nano Tio2 ◽  
Sem Images ◽  
Fouling Control ◽  
Membrane Surfaces ◽  
Cake Layer

TiO2 photocatalytic oxidation was combined with microfiltration (MF) (PCOMF) to remove humic acid (HA) in waters through investigating the flux performance, TOC, UV254 and UV436 removal efficiency, the fouled membrane surfaces by SEM. The results demonstrated that the combined PCOMF process showed a high removal efficiency of UV254 and UV436 of HA (close to 100%). The removal efficiency of TOC was about 84.34% indicating that most of HA was mineralized into water and carbon. The SEM images witnessed that the fouling on the membrane surfaces contaminated by PCO effluents after UV254 and UV365 light irradiation was mainly attributed to cake layer, which was reversible due to the increase of aggregated particles size consisting of HA and TiO2. Eventually, the combined PCOMF process displayed an improved effect on HA removal and fouling control to a certain level.

scholarly journals Proof of Concept for Light Conducting Membrane Substrate for UV-Activated Photocatalysis as an Alternative to Chemical Cleaning

Membranes ◽  
2018 ◽  
Vol 8 (4) ◽  
pp. 122 ◽  
Author(s):  
Lavern Nyamutswa ◽  
Bo Zhu ◽  
Dimuth Navaratna ◽  
Stephen Collins ◽  
Mikel Duke
Keyword(s):  
Organic Matter ◽  
Humic Acid ◽  
Natural Organic Matter ◽  
Membrane Fouling ◽  
Ceramic Membrane ◽  
Current Method ◽  
Dip Coating ◽  
Polluted Water ◽  
Chemical Cleaning ◽  
Cake Layer

Adopting an effective strategy to control fouling is a necessary requirement for all membrane processes used in the water/wastewater treatment industry to operate sustainably. The use of ultraviolet (UV) activated photocatalysis has been shown to be effective in mitigating ceramic membrane fouling by natural organic matter. The widely used configuration in which light is directed through the polluted water to the membrane’s active layer suffers from inefficiencies brought about by light absorption by the pollutants and light shielding by the cake layer. To address these limitations, directing light through the substrate, instead of through polluted water, was studied. A UV conducting membrane was prepared by dip coating TiO2 onto a sintered glass substrate. The substrate could successfully conduct UV from a lamp source, unlike a typical alumina substrate. The prepared membrane was applied in the filtration of a humic acid solution as a model compound to study natural organic matter membrane fouling. Directing UV through the substrate showed only a 1 percentage point decline in the effectiveness of the cleaning method over two cleaning events from 72% to 71%, while directing UV over the photocatalytic layer had a 9 percentage point decline from 84% to 75%. Adapting the UV-through-substrate configuration could be more useful in maintaining membrane functionality during humic acid filtration than the current method being used.

scholarly journals Ultrafiltration fouling behavior of natural organic matter: a perspective of EEM and molecular weight distribution

2021 ◽  
Author(s):  
Gao Kuo ◽  
Song Yuan
Keyword(s):  
Molecular Weight ◽  
Organic Matter ◽  
Humic Acid ◽  
Natural Organic Matter ◽  
Membrane Fouling ◽  
Microbial Product ◽  
Membrane Morphology ◽  
Atomic Force ◽  
Fluorescence Characteristics ◽  
Cake Layer

Abstract As the natural organic matter (NOM) can cause serious ultrafiltration (UF) membrane fouling, most previous studies on UF fouling caused by NOM focused on the contribution of NOM characteristics. In this study, the correlation of molecular weight and fluorescence characteristics was examined and the fouling behavior of NOM were examined in a comprehensive manner through a lot of analysis including the redundancy analysis (RDA), parallel factor analysis (PARAFAC) and atomic force microscope (AFM). The results showed that NOM from Tong Xin river was composed of humic acid (500 Da–8,000 Da), tryptophan-like substance, soluble microbial product (SMP) and aromatic protein (600,000 Da–2,000,000 Da).Notably, UF performance was significantly affected by the humic acid-like substance. Concurrently, the combined mechanism (CM) model was adopted to evaluate the fouling mechanism of NOM. The results indicated that cake-intermediate model played an important part during membrane fouling and the cake layer fouling had a larger predominance over the intermediate blocking which can be further proved in the membrane morphology detection.

Characterization of dissolved organic matter (DOM) extracted from soils by hot water percolation (HWP)

2010 ◽  
Vol 59 (1) ◽  
pp. 99-108 ◽  
Author(s):  
M. Takács ◽  
Gy. Füleky
Keyword(s):  
Organic Matter ◽  
Humic Acid ◽  
Natural Organic Matter ◽  
Extraction Methods ◽  
Soil Samples ◽  
Hot Water ◽  
Soil Extracts ◽  
Water Percolation ◽  
Soil Humic Acid

The Hot Water Percolation (HWP) technique for preparing soil extracts has several advantages: it is easily carried out, fast, and several parameters can be measured from the same solution. The object of this study was to examine the possible use of HWP extracts for the characterization of soil organic matter. The HPLC-SEC chromatograms, UV-VIS and fluorescence properties of the HWP extracts were studied and the results were compared with those of the International Humic Substances Society (IHSS) Soil Humic Acid (HA), IHSS Soil Fulvic Acid (FA) and IHSS Suwannee Natural Organic Matter (NOM) standards as well as their HA counterparts isolated by traditional extraction methods from the original soil samples. The DOM of the HWP solution is probably a mixture of organic materials, which have some characteristics similar to the Soil FA fractions and NOM. The HWP extracted organic material can be studied and characterized using simple techniques, like UV-VIS and fluorescence spectroscopy.

Effects of Natural Organic Matter on TCE Removal in Groundwater by Zero-Valent Iron: Batch Study

2013 ◽  
Vol 807-809 ◽  
pp. 486-489
Author(s):  
Tong Zhou Liu ◽  
Pin Hua Rao
Keyword(s):  
Organic Matter ◽  
Humic Acid ◽  
Natural Organic Matter ◽  
Early Stage ◽  
Organic Contaminant ◽  
Zero Valent Iron ◽  
Contaminant Removal ◽  
Inhibitory Effects ◽  
Batch Study

An investigation on the effects of humic acid (representing NOM) on TCE (a typical organic contaminant) removal by Fe0in batch settings was carried out. Inhibitory effects of humic acid on Fe0towards TCE removal were observed. At early stage of the experiments, humic acid might partition with TCE, and the adsorption or deposition of humic acid onto Fe0surface would further facilitated TCE immobilization. Once the reduction reactive sites on Fe0surfaces were covered by accumulated humic acid and the partition of TCE to humic acid became saturated, TCE removal in Fe0was observed retarded.

scholarly journals Molecular characterization of an end-residue of humeomics applied to a soil humic acid

RSC Advances ◽  
2014 ◽  
Vol 4 (45) ◽  
pp. 23658-23665 ◽  
Author(s):  
A. Nebbioso ◽  
A. Piccolo ◽  
M. Lamshöft ◽  
M. Spiteller
Keyword(s):  
Organic Matter ◽  
Humic Acid ◽  
Molecular Characterization ◽  
Natural Organic Matter ◽  
Molecular Composition ◽  
Chemical Fractionation ◽  
Soil Humic Acid

Humeomics encompasses step-wise chemical fractionation and instrumental determination to fully characterize the heterogeneous molecular composition of natural organic matter.

Interactions of hypochlorite ion and humic acid: photolytic and photocatalytic pathways

2001 ◽  
Vol 44 (5) ◽  
pp. 205-210 ◽  
Author(s):  
D. Gonenç ◽  
M. Bekbolet
Keyword(s):  
Humic Acid ◽  
Reaction Kinetics ◽  
Removal Efficiency ◽  
Photocatalytic Oxidation ◽  
Removal Rate ◽  
Order Reaction ◽  
First Order Reaction ◽  
Acid Oxidation ◽  
First Order ◽  
Toc Removal

Photolytic and photocatalytic interactions of hypochlorite ion and humic acid are investigated under various conditions. Humic acid oxidation by aqueous chlorine under dark conditions are expressed in terms of first order reaction kinetics. Upon irradiation (300 nm < λ < 400 nm), photolysis of aqueous chlorine affect the removal efficiency of humic acid via oxidation. TiO2 sensitised photocatalytic oxidation conditions reveal an increase in the TOC removal rate of humic acid in the presence of aqueous chlorine. Under the specified conditions, increasing the photocatalyst loading up to 1.0 mg/mL markedly increase the TOC removal rate.

scholarly journals Effect of Natural Organic Matter on the Ozonation Mechanism of Trimethoprim in Water

Water ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2935
Author(s):  
Ning Zhang ◽  
Beihai Zhou ◽  
Rongfang Yuan ◽  
Fei Wang ◽  
Huilun Chen
Keyword(s):  
Organic Matter ◽  
Free Radical ◽  
Natural Organic Matter ◽  
Removal Efficiency ◽  
Bacterial Infections ◽  
Degradation Mechanism ◽  
Degradation Pathways ◽  
Ozonation Time ◽  
Direct Hydroxylation ◽  
Fluorescence Peak

Trimethoprim (TMP) is often used for the treatment of various bacterial infections. It can be detected in water, and it is difficult to be biodegraded. In this study, the degradation mechanism of TMP through ozonation and the effect of humic acids (HA) were investigated. Excessive ozone (pH 6, 0 °C) could reduce the content of TMP to less than 1% in 30 s. However, when ozone (O3) was not excessive (pH 6, 20 °C), the removal efficiency of TMP increased with the increase of O3 concentration. Four possible degradation pathways of TMP in the process of ozonation were speculated: hydroxylation, demethylation, carbonylation, and cleavage. The presence of HA in water inhibit the generation of ozonation products of TMP. The excitation-emission matrices (EEM) analysis showed that with the extension of ozonation time, the fluorescence value in the solution decreased and the fluorescence peak blue shifted. These results indicated that the structure of HA changed in the reaction and was competitively degraded with TMP. According to the free radical quenching test, the products of pyrolysis, direct hydroxylation and demethylation were mainly produced by indirect oxidation.

Identification of humic acid-like and fulvic acid-like natural organic matter in river water using fluorescence spectroscopy

2011 ◽  
Vol 63 (10) ◽  
pp. 2427-2433 ◽  
Author(s):  
R. H. Peiris ◽  
H. Budman ◽  
C. Moresoli ◽  
R. L. Legge
Keyword(s):  
Organic Matter ◽  
Humic Acid ◽  
Water Sample ◽  
Fulvic Acid ◽  
River Water ◽  
Natural Organic Matter ◽  
Drinking Water Treatment ◽  
Fluorescence Analysis ◽  
Product Formation ◽  
Fluorescence Excitation

Identifying the extent of humic acid (HA)-like and fulvic acid (FA)-like natural organic matter (NOM) present in natural water is important to assess disinfection by-product formation and fouling potential during drinking water treatment applications. However, the unique fluorescence properties related to HA-like NOM is masked by the fluorescence signals of the more abundant FA-like NOM. For this reason, it is not possible to accurately characterize HA-like and FA-like NOM components in a single water sample using direct fluorescence EEM analysis. A relatively simple approach is described here that demonstrates the feasibility of using a fluorescence excitation-emission matrix (EEM) approach for identifying HA-like and FA-like NOM fractions in water when used in combination with a series of pH adjustments and filtration steps. It is demonstrated that the fluorescence EEMs of HA-like and FA-like NOM fractions from the river water sample possessed different spectral properties. Fractionation of HA-like and FA-like NOM prior to fluorescence analysis is therefore proposed as a more reasonable approach.

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