Effect of inorganic ions on the photocatalytic degradation of humic acid

Yan, Xuehai; Bao, Ruiling; Yu, Shuili

doi:10.1134/s0036024412060313

Cited by 20 publications

(5 citation statements)

References 17 publications

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“…Considering the inhibition of photocatalytic reaction by ions responsible for water hardness, it must be noted, that on the one hand Ca 2+ and Mg 2+ ions in tap water are able to form complexes with humic substances (FA) what decreases their solubility and favors the adsorption on TiO 2 surface. On the other hand, Mg 2+ ions may react with organic substances responsible for water color and generate hardly degradable compounds, which affect photocatalytic reaction rate [9][10][11]. Precipitation of carbonates on the glass UV lamp cover was also observed during experiments, what surely affected the effective UV radiation in water solution and, the same, decreased the degradation rate of organic compounds.…”

Section: Impact Of Water Hardness On the Kinetics Of Decomposition Ofmentioning

confidence: 99%

“…Probably, the lower rate of the photocatalytic reaction observed in surface water II was the result of a negative impact of anions on the TiO 2 catalyst action. Anions are very strong sweepers of hydroxyl radicals OH • and electron gaps, what weakens the adsorption of humic substance on TiO 2 surface [2,9]. Moreover, the inhibition of the photocatalytic reaction cause by anions is also caused by the adsorption affinity to OH ions bonded with the catalyst surface.…”

Section: Impact Of the Chemical Composition Of Water On The Kinetics mentioning

confidence: 99%

“…SO , HCO   on the process is the subject of the interest [9]. Very interesting conclusions, however, often differ from each other, depending on the type of contaminants present in water as well as on their interactions.…”

Section: Introductionmentioning

confidence: 99%

“…The results of the studies performed by many researchers indicate that at certain conditions the presence of positive ions may improve the degradation of organic compounds during photocatalysis, however those ions may become process inhibitors as well [10,11]. Negative ions generally cause the decrease of the photocatalytic decomposition rate of organic compounds [9]. The knowledge on the impact of inorganic ions but also of other factors on the effectiveness of photocatalysis is very important for proper configuration of photocatalytic reactors operation.…”

Section: Introductionmentioning

confidence: 99%

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Impact of the water composition on the degradation kinetics of natural organic matter in photocatalytic membrane reactors

Rajca

2015

Environ. Protect. Eng.

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Decomposition kinetics of natural organic substances during the photocatalytic process with a semiconductor TiO 2 has been investigated. In the study, a laboratory reactor Heraeus and in a photocatalytic membrane reactor were used. Simulated solutions of deionized water, surface water and fulvic acids, differing in composition, were tested in the experiment. In order to determine reaction rate constants, the Langmuir-Hinshelwood kinetic model based on the first order reaction was applied. It was found that photocatalytic process enabled effective degradation of natural organic substances although its run was affected by inorganic ions, mainly those producing water hardness, present in water.

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Section: Impact Of Water Hardness On the Kinetics Of Decomposition Ofmentioning

confidence: 99%

Section: Impact Of the Chemical Composition Of Water On The Kinetics mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Impact of the water composition on the degradation kinetics of natural organic matter in photocatalytic membrane reactors

Rajca

2015

Environ. Protect. Eng.

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“…4). This is due to the fact that these anion species can likely enhance the adsorption of NOMs (especially the humic acid components) on the catalyst [223].…”

Section: Role Of Co-existing Inorganic Anion Speciesmentioning

confidence: 99%

Micropollutant degradation in water by photochemical processes

Yin¹

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Fast growing global population and economy result in an increasing water consumption worldwide. However, the amounts of usable water resources are limited: more than one-third of the accessible renewable fresh water on Earth is being exploited for industrial, agricultural, as well as domestic usage [1]. Locally, especially in water scarce areas, this is often reaching much higher levels, leading to overdraft of water resources [2]. Such facts call for the need to not only exploit new and alternative water resources but also to recycle water streams, to cope with the unfortunate increasing limitations in availability of fresh water sources. Meanwhile, the fast growing population and economy are leading to serious water pollution due to discharge of numerous contaminants into the environment, which in turn possess sever threats to the quality of water resources. Thus, the increasing worldwide demand for water consumption, the limited amount of water resources, and the water pollution make water treatment a vital measure to safeguard the water supply with sufficient quantity and quality that meets the demand of the society. Conventionally, concerns were given to pathogens, nutrients, heavy metals, suspended solids, and bulk organic pollutants (the amount of bulk organic pollutants generally present in concentrations at 0.1-10 g/l in waste water and often denoted with COD or BOD, meaning chemical or biological oxygen demand). Thus in most parts of the world water purification measures have been taken to tackle these problems [3, 4]. In recent decades, many emerging organic pollutants (generally present at rather low concentrations, i.e. ng/L to µg/L level, and therefore also termed as micropollutants). These include pharmaceuticals, antibiotics, herbicides, pesticides, chemicals from personal care products, etc., and have been detected the last two decades extensively in different water bodies worldwide. For instance, many pharmaceuticals were found in various portions of the aquatic system, i.e. in ground water, surface water, as well as in many drinking water sources according to a broad range of studies [5-11]. In a study conducted by Félix-Cañedo et al. in Mexico City, the presence of a group of organic micropollutants (including pharmaceuticals, hormones, herbicides) in several drinking water sources was reported, at concentrations ranging from ng/L to µg/L level [12]. In recent years, a broad range of micropollutants, including Other investigated homogeneous photochemical processes include UV/Cl2, UV/O3, UV/HOCl, UV/ClO2. Application of these techniques for removal of various micropollutants has been studied over last decades. It is reported that UV/Cl2 could achieve relatively good removal of carbamazepine from wastewater, but formation of toxic chlorinated byproducts was an issue [132, 133]. Kong et al. reported efficient degradation of atrazine by UV/Cl2 [134]. Examples of micropollutant removal by UV/O3, UV/HOCl, UV/ClO2, etc., are also abundant in literature [135-138]. 1.3 Research opportunities 1.3.1 Rese...

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