ABSTRACT
Laboratory studies were conducted to determine the effect of pH and redox conditions, as well as the effect of Fe, Mn, Ca, Al, and organic matter, on the release of ortho‐phosphates in lake ...sediments taken from Lakes Koronia and Volvi (Northern Greece). Results were evaluated in combination with experiments to determine P fractionation in the sediment. The study revealed the major effect of redox potential and pH on the release of P from lake sediments. Both lakes showed increased release rates under reductive conditions and high pH values. The fractionation experiments revealed increased mobility of the reductive P fraction as well as of the NaOH‐P fraction, indicating participation of both fractions in the overall release of sediment‐bound P, depending on the prevailing environmental conditions. The results were assessed in combination with the release patterns of Fe, Mn, Ca, Al, and organic matter, enabling the identification of more specific processes of P release for each lake. The basic release patterns included the redox induced reductive dissolution of P‐bearing metal oxides and the competitive exchange of phosphate anions with OH− at high pH values. The formation of an oxidized surface microlayer under oxic conditions acted as a protective film, preventing further P release from the sediments of Lake Volvi, while sediments from Lake Koronia exhibited a continuous and increased tendency to release P under various physicochemical conditions, acting as a constant source of internal P loading.
•Evaluation of acetamiprid degradation using Fenton.•Investigation of the effect of different concentrations of H2O2 and Fe2+.•Evaluation of various initial pH and different iron salts as Fe2+ and ...Fe3+ sources.•Application of response surface methodology in the evaluation of the process kinetics.•Investigation of the use of zero valent iron as a constant source of ferrous ions.
The aims of this study were (a) to evaluate the degradation of acetamiprid with the use of Fenton reaction, (b) to investigate the effect of different concentrations of H2O2 and Fe2+, initial pH and various iron salts, on the degradation of acetamiprid and (c) to apply response surface methodology for the evaluation of degradation kinetics.
The kinetic study revealed a two-stage process, described by pseudo- first and second order kinetics.
Different H2O2:Fe2+ molar ratios were examined for their effect on acetamiprid degradation kinetics. The ratio of 3mgL−1 Fe2+: 40mgL−1 H2O2 was found to completely remove acetamiprid at less than 10min. Degradation rate was faster at lower pH, with the optimal value at pH 2.9, while Mohr salt appeared to degrade acetamiprid faster.
A central composite design was selected in order to observe the effects of Fe2+ and H2O2 initial concentration on acetamiprid degradation kinetics. A quadratic model fitted the experimental data, with satisfactory regression and fit. The most significant effect on the degradation of acetamiprid, was induced by ferrous iron concentration followed by H2O2. Optimization, aiming to minimize the applied ferrous concentration and the process time, proposed a ratio of 7.76mgL−1 Fe(II): 19.78mgL−1 H2O2. DOC is reduced much more slowly and requires more than 6h of processing for 50% degradation. The use to zero valent iron, demonstrated fast kinetic rates with acetamiprid degradation occurring in 10min and effective DOC removal.
This study presents the development of an analytical method for the simultaneous determination of multiclass illicit drugs (cocainoids, opiates, amphetamines, and cannabinoids) and psychoactive ...pharmaceuticals (anxiolytics, hypnotics, antipsychotics, antidepressants, and antiparkinsonian), in municipal wastewater. The analytical method was validated in terms of specificity, linearity, precision, and accuracy. The recoveries (%) for the majority of the analytes ranged between 70 and 120%, while the method showed good repeatability (2.4–29.2%). The limits of detection (LOD) of the method ranged between 0.8 and 9.4 ng L
−1
. The method was implemented on influent and effluent samples from Thessaloniki (N. Greece) wastewater treatment plant (WWTP), and it revealed the daily presence of benzoylecgonine (BEG) (84.0–202.2 ng L
−1
), methadone (12.3–17.5 ng L
−1
), 11-Nor-9-carboxy-Δ
9
-tetrahydrocannabinol (THC-COOH) (80.3–171.9 ng L
−1
), morphine (144.2–264.3 ng L
−1
), and 6-monoacetylmorphine (6-MAM) (5.8–12.0 ng L
−1
) in the influent samples of WWTP. Clozapine (101.6–315.5 ng L
−1
), quetiapine (33.5–109.7 ng L
−1
), and fluoxetine (20.9–124.4 ng L
−1
) were pharmaceutical psychotics with the highest concentration in the influents. Back calculation estimated that the daily consumption of cocaine, heroin, cannabis, and methadone was 36–95, 86–164, 2300–5400, and 8–12 mg day
−1
per 1000 inhabitants, respectively. The consumption was estimated between 7–16 and 15 mg day
−1
per 1000 inhabitants for methyl diethanolamine (MDEA) and 3,4-methylenedioxymethamphetamine (MDMA), respectively.
Graphical Abstract
The presence of phosphorus (P) and heavy metals (HMs) in surface sediments originating from lakes Volvi, Kerkini, and Doirani (N. Greece), as well as their fractionation patterns, were investigated. ...No statistically significant differences in total P content were observed among the studied lakes, but notable differences were observed among sampling periods. HM contents in all lakes presented a consistent trend, i.e., Mn > Cr > Zn > Pb > Ni > Cu > Cd, while the highest concentrations were recorded in Lake Kerkini. Most of the HMs exceeded probable effect level value indicating a probable biological effect, while Ni in many cases even exceeded threshold effects level, suggesting severe toxic effects. P was dominantly bound to metal oxides, while a significant shift toward the labile fractions was observed during the spring period. The sum of potentially bioavailable HM fractions followed a downward trend of Mn > Cr > Pb > Zn > Cu > Ni > Cd for most lakes. The geoaccumulation index
I
geo
values of Cr, Cu, Mn, Ni, and Zn in all lakes characterized the sediments as “unpolluted,” while many sediments in lakes Volvi and Kerkini were characterized as “moderately to heavily polluted” with regard to Cd. The descending order of potential ecological risk
E
r
i
was Cd > Pb > Cu > Ni > Cr > Zn > Mn for all the studied lakes. Ni and Cr presented the highest toxic risk index values in all lake sediments. Finally, the role of mineralogical divergences among lake sediments on the contamination degree was signified.
An automated flow method for the determination of hydrazine based on the concept of zone-fluidics has been developed. The analyte reacts under flow conditions with
-dimethylamino benzaldehyde (25 ...mmol L
) in micellar medium (100 mmol L
SDS) to form a stable derivative (460 nm). Micelles mediated catalysis excludes the use of highly acidic environment typical for this kind of reaction. Following careful examination of chemical and instrumental variables, the method allows the determination of hydrazine at the low micromolar level (0.3-10 μmol L
) in water samples. Real sample analyses (drinking and boiler feed water) resulted in satisfactory results in terms of accuracy with the percent recoveries being in the range of 82-114%.
In the present report, the oxidative degradation of an endocrine-disrupting compound triadimenol has been investigated using the photo-Fenton reaction. Different reaction conditions that affected the ...degradation kinetics were examined including the iron (Fe
2+
) ions and hydrogen peroxide (H
2
O
2
) concentrations, the initial concentration of triadimefon, and the type of iron salt. The degradation rates proved to be strongly influenced by the above parameters. The reaction conditions in terms of Fe
2+
and H
2
O
2
concentrations were systematically studied and optimized using an experimental design through central composite design. The kinetics of the process can be characterized as pseudo-first-order. As iron and hydrogen peroxide concentrations increase, the degradation rate of triadimenol accelerates and complete degradation can be achieved after a short time of illumination. The effectiveness of the five different iron salts on the degradation performance were also investigated. Experiments with longer time illumination can lead to complete mineralization and detoxification of triadimenol solutions. The properties of the proposed oxidative degradation scheme make it a promising candidate for wastewater treatment.
The pulp and paper industry have historically been one of the world's largest consumers of freshwater resources and producers of wastewater discharges. More than 250 chemicals have been identified in ...effluents including chlorine-based organic and other toxic compounds. Some of these are resistant to biological degradation such as color-related compounds. The goal of this study was to analyze the real wastewater from the paper mill and to suggest a photocatalytic treatment method in order to reduce the organic pollutants load. The efficiency of the commonly used treatment photocatalytic processes (photo-TiO.sub.2 and photo-Fenton reagent) on the treatment of real paper mill effluent was investigated. Additionally, the performance of TiO.sub.2 photocatalytic reactions with and without the addition of hydrogen peroxide was also examined. For the experiment, a 500 mL pyrex UV reactor and a 125-W high-pressure mercury lamp, surrounded by pyrex filter blocking wavelengths below 290 nm were used. The approach has been applied for the treatment of effluents produced from a papermaking industry.
The pulp and paper industry have historically been one of the world’s largest consumers of freshwater resources and producers of wastewater discharges. More than 250 chemicals have been identified in ...effluents including chlorine-based organic and other toxic compounds. Some of these are resistant to biological degradation such as color-related compounds. The goal of this study was to analyze the real wastewater from the paper mill and to suggest a photocatalytic treatment method in order to reduce the organic pollutants load. The efficiency of the commonly used treatment photocatalytic processes (photo-TiO
2
and photo-Fenton reagent) on the treatment of real paper mill effluent was investigated. Additionally, the performance of TiO
2
photocatalytic reactions with and without the addition of hydrogen peroxide was also examined. For the experiment, a 500 mL pyrex UV reactor and a 125-W high-pressure mercury lamp, surrounded by pyrex filter blocking wavelengths below 290 nm were used. The approach has been applied for the treatment of effluents produced from a papermaking industry.
A novel pilot plant for the electrochemical treatment of textile wastewater is discussed in this paper. The process is based on the electrolytic degradation of azodyes, applying a specific potential ...with on line measurement of current, pH and temperature. Batch experiments are performed for single electrolytic cell and continuous flow experiments for serial electrolytic cell apparatus (cascade system), using both synthetic and real wastewater samples. For synthetic samples treatment, four commercially pure azodyes (Reactive Orange 91, Reactive Red 184, Reactive Blue 182 and Reactive Black 5) are used, while sodium chloride (NaCl) and sodium sulfate (Na
2SO
4) are tested as supporting electrolytes. Real wastewater treatment under optimal conditions yield 94.4% dye removal and neutral final pH. Biologically Oxygen Demand measured after 5 days (BOD
5) and Chemically Oxygen Demand (COD) values are reduced by 35 and 45%, respectively, while COD/BOD
5 ratio is reduced from 4.3 to 3.6 final value. The proposed pilot plant achieves almost complete decoloration requiring no further addition of electrolyte or any other chemical agent. Thus, it could easily be used as a pretreatment stage prior to biological treatment.
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