V. F. Vakulenko

Photocatalytic destruction of fulvic acids by oxygen in the TiO2 suspension

The paper presents a short review of the published data dealing with the photocatalytic (O2/TiO2/UV) oxidation of humic and fulvic acids that represent main organic impurities of natural waters. The possibility of achieving a deep destruction (≥ 90% in terms of TOC) of fulvic acids separated from the water of the Dnieper River during the process of photocatalytic oxidation by oxygen was shown for a wide interval of pH (3–8). The photocatalytic activity of a series of commercial TiO2 samples in different isomorphic states was estimated and the impact of certain parameters of photocatalytic oxidation on the degree of complete destruction of fulvic acids was determined.

Formation and decomposition of hydrogen peroxide during UV-radiation, ozonization, and O3/UV treatment of river water

We have studied the kinetics of the formation of hydrogen peroxide during UV-radiation, ozonization, and O3/UV treatment of water of the Dnieper River and model solutions of fulvic acids. We have also investigated decomposition of added hydrogen peroxide at the indicated methods of treating river and model waters and the impact of H2O2 on the concentration of dissolved ozone.

Photocatalytic destruction of fulvic acids by ozone and oxygen

abstractWe have studied destruction of river fulvic acids in water environment with ozone and oxygen. We have also determined advantages of catalytic and photocatalytic ozonization of their solutions compared with ozonization and O3/UV treatment. Photocatalytic ozonization secures the highest degree of destruction of fulvic acids (93% in terms of total organic carbon) at a shorter time and specific consumption of ozone compare with other methods of oxidation.

Photocatalytic destruction of anionic SAS with oxygen and hydrogen peroxide in the TiO2 suspension

The articles gives a comparison of the rates and the degree of destruction of anionic SAS-alkyl benzene sodium sulfonate (ABS) in heterogeneous (O2/TiO2/UV, H2O2/TiO2/UV) and homogeneous (O2/UV, H2O2/UV) oxidizing systems on several TiO2 samples at UV irradiation by a SVD-120 high-pressure mercury-quartz lamp. The paper has demonstrated a possibility of achieving a high degree of photocatalytic destruction of ABS by hydrogen peroxide (100, 90, and 80% respectively by the ABS concentration of ABS, COD, and TOC over two hours).

Impact of hydrogen peroxide on the destruction degree of fulvic acids and organic impurities of river water by ozone, UV radiation, and O3/UV treatment

We have investigated the impact of hydrogen peroxide on the change of the generalized indicators of water quality of the Dnieper River and model solutions of fulvic acids in UV radiation, ozonization, and O3/UV treatment. We confirmed its involvement in the oxidation process of organic impurities by all studied methods at the pH of the medium more than 7. However, the additions of 1–5 mg/dm3 of hydrogen peroxide inhibited the destruction of fulvic acid in a weakly acidic medium (pH 6.3) and reduced the mineralization degree of water impurities of the Dnieper River during O3/UV treatment and do note accelerate discoloration of the samples under investigation at the studied parameters of ozonization and O3/UV treatment.

Photocatalytic destruction of anionic SAS by ozone and oxygen

The article has investigated photocatalytic destruction of anionic SAS—sodium alkylbenzene sulfate (ABS) in the aqueous medium by ozone on TiO2 Degussa P-25 at UV radiation by a DB-15 low-pressure mercury-quartz lamp. The paper has determined the parameters of photocatalytic ozonization securing complete ABS destruction (100% in terms of organic carbon). We have assessed advantages of photocatalytic ozonization of ABS solutions compared with photocatalytic oxidation by oxygen and O3/UV treatment.

Impact of polyhexamethylene guanidine hydrochloride on the process of coagulation treatment of river waters

The paper has investigated flocculation capacity of polyhexamethylene guanidine hydrochloride during joint treatment with aluminum sulfate of the Dnieper and Desna River water in the spring period. It has been shown that additives 1–5 mg/dm3 of the matter under study during coagulation treatment of the river waters improves the process of their clarification, increases the filtrate quality in terms of main indicators and makes it possible to reduce by 10–20 mg/dm3 the dose of the coagulant. A pronounced flocculation effect manifests itself when treating the waters in question by the doses of a polymer preparation respectively 3–5 and 2–3 mg/dm3. Polyhexamethylene guanidine (without a coagulant) ensures a standardized quality of the filtrate in terms of color and turbidity only when treating weakly stained water of the Desna River. It has been found that ≥ 99% of polyhexamethylene guanidine is retained by the medium of a sand filter.

The impact of UV radiation on the decomposition kinetics of cationic SAS with ozone in an aqueous medium

The paper studied the kinetics of destruction of alkylpyridinium bromides in ozonization, UV radiation, and O3/UV treatment of their model solutions. We demonstrated expediency of using O3/UV treatment for decomposition of cationic SAS of the above type in an aqueous medium close to a neutral one (pH 6–8). We have determined the process parameters ensuring a synergetic nature of the joint effect of ozone and UV radiation on the compounds under study.

The study of properties and catalytic activity of titanium dioxide doped with sulphure

Comparison was made by activity of TiO2 doped with sulphur (S-TiO2) and pure TiO2, synthesized by the sol-gel method, with TiO2 Degussa P-25 in course of photocatalytic oxidation by oxygen of the air of aqueous solutions of fulvic acids, humic and picric acids at two modes of radiation by a SVD-120 lamp (λ > 200 or λ > 320 nm). It is shown that at oxidation of fulvic acids and humic acid the activity of S-TiO2 is substantially higher than the activity of pure TiO2 under both modes of radiation, however, under conditions of the experiment the given samples were less effective at oxidation by picric acid.

Substatiation of technological modes for effective operation of oxidative-sorption units of water treatment

The paper assessed the degree of oxidative-sorption purification of model waters on a local unit of drinking water conditioning, capacity up to 1 m3/h. It is shown that the quality of the effluent in terms of generalized indicators characterizing the total content of organic impurities, corresponds to regulatory requirements for drinking water. The replacement of ozonization with O3/UV treatment increases the fraction of absorbed ozone and the destruction degree of organic impurities. The degree of oxidative-sorption of water treatment by all parameters being controlled is higher than the adsorption one.