A kinetic model describing Fenton and photo-Fenton degradation of paracetamol (PCT) and consumption of hydrogen peroxide (H₂O₂) was proposed. A set of Fenton and photo-Fenton experiments (18 runs in total) was performed by fixing the initial concentration of PCT to 40 mg L⁻¹ and varying the initial concentrations of H₂O₂ and ferrous ion, Fe²⁺. The experimental set-up was a well-stirred annular photoreactor equipped with an actinic BL TL-DK 36 W/10 1SL lamp. Experimental results highlighted that PCT is no more detected by HPLC analysis within a minimum reaction time of 2.5 and a maximum reaction time of 15.0 min. Besides, a maximum conversion of total organic carbon (TOC) of 68.5% was observed after 75 min of reaction in case of using UV radiation and the highest concentrations of the Fenton reagents. The experimental data were used to fit the kinetic model. The radiation field inside the reactor was taken into account through the local volumetric rate of photon absorption, evaluated by assuming a line source model with spherical and isotropic emission. The kinetic parameters were estimated by using a non-linear least-squares regression procedure and root mean square errors (RMSE) were calculated in order to validate the feasibility of the proposed model. A good agreement between experimental and predicted data was observed and the lowest values of RMSE resulted in 5.84 and 9.59% for PCT and H₂O₂ normalized concentrations, respectively.

The presence of pathogens in drinking water can seriously affect human health. Therefore, water disinfection is needed, but conventional processes, such as chlorination, result in the production of dangerous disinfection by-products. In this regard, an alternative solution to tackle the problem of bacterial pollution may be the application of advanced oxidation processes. In this work, the inactivation of total coliforms, naturally present in a Colombian surface water by means of UV/H₂O₂, UV/US, and the UV/US/H₂O₂ advanced oxidation processes, was investigated. Under the investigated conditions, complete bacterial inactivation (detection limit equal to 1 CFU 100 mL⁻¹) was found within 5 min of treatment by UV/H₂O₂ and UV/US/H₂O₂ systems. UV/US oxidation process also resulted in total bacterial load elimination, but after 15 min of treatment. Bacterial reactivation after 24 h and 48 h in the dark was measured and no subsequent regrowth was observed. This phenomenon could be attributed to the high oxidation capacity of the evaluated oxidation systems. However, the process resulting in the highest oxidation potential at the lowest operating cost, in terms of energy consumption, was UV/H₂O₂ system. Therefore, UV/H₂O₂ advanced oxidation system can be used for disinfection purposes, enabling drinking water production meeting the requirements of regulated parameters in terms of water quality, without incurring extremely high energy costs. Nonetheless, further researches are required for minimizing the associated electric costs.

In order to improve the catalytic properties of Fe₃O₄ nanoparticles in wastewater treatment, the Cu-doped Fe₃O₄/graphene oxide (Fe₃₋ₓCuₓO₄/GO) nanocomposites were prepared by a modified co-precipitation method and used as heterogeneous catalyst for p-Nitrophenol (p-NP) degradation. The effect of the GO and Cu contents in the nanocomposites was investigated. Compared with the unsupported Fe₃O₄ nanoparticles, the Fe₃O₄/GO nanocomposites have obviously improved catalytic performance, especially for the nanocomposite with 6.25 wt.% of the GO content. Furthermore, the catalytic efficiency is greatly improved by doping Cu in the nanocomposite. The Fe₃₋ₓCuₓO₄/GO nanocomposite achieves the best catalytic property in our catalyst system when the x value is about 0.075. Under the optimal reaction condition (0.8 g L⁻¹ of catalyst dosage, 15 mmol L⁻¹ of initial H₂O₂ concentration, 3.0 of pH value, and 30 °C of temperature), the p-NP conversion and chemical oxygen demand removal efficiencies in 120 min for the Fe₂.₉₂₅Cu₀.₀₇₅O₄/GO nanocomposite are about 98.4% and 74.7%, respectively. And the p-NP conversion efficiency is still as high as 96.2% after four recycles under the optimum condition. The results clearly show that the Fe₂.₉₂₅Cu₀.₀₇₅O₄/GO nanocomposite has outstanding catalytic properties for the p-NP degradation.

Brownfields have attracted increasing attentions from both researchers and practitioners. However, few studies have attempted to make a comprehensive and quantitative review on this topic. This study conducted a scientometric review on the brownfield research from 1995 to 2017 using CiteSpace. The knowledge structure, hot topics, research trends, and gaps were analyzed based on the co-author, co-word, co-citation, and clusters analysis. Six hundred thirty articles from the Web of Science core collection database were selected as the research samples. Results revealed that the research focus has changed from soil remediation technologies to sustainable regeneration methods. The most vital development in brownfield research occurred in the USA, England, Canada, Germany, and China. “Brownfield,” “heavy metal,” “remediation,” “redevelopment,” and “sustainability” were the most frequently used keywords. Whereas “management” and “biodiversity” received citation bursts in recent years. Existing researches mainly concentrated on subject categories of environmental sciences ecology, environmental sciences, engineering, environmental studies, engineering environmental, and urban studies. Sustainable regeneration, urban brownfields’ regeneration, mental distribution, coal-mine brownfield, and ecosystem service were the identified co-citation clusters and represented the hot topics and emerging trends. The research gaps can serve as a motivation to research on the next generation of brownfields to support the sustainable development. This study provides researchers and practitioners an extensive and intensive understanding of the salient research themes and trends of brownfields’ research worldwide.

In the present work, graphene oxide (GO) was synthesized via the modified Hummers method and utilized in treating real soil washing wastewater via adsorptive removal of lead (Pb) and zinc (Zn). Characterization analysis of GO was performed using X-ray diffraction, Brunauer-Emmett-Teller method, Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, and zeta potential analysis. The Van’t Hoff, Eyring, and Arrhenius equations were applied to determine the activation and thermodynamic parameters namely activation energy (Eₐ), standard Gibbs energy change (ΔG°), standard enthalpy change (ΔH°), standard entropy change (ΔS°), change in activation Gibbs energy (ΔG#), change in activation enthalpy (ΔH#), and change in activation entropy (ΔS#). Based on the high coefficient of determination values (0.8882 ≥ R² ≥ 0.9094) and low values of SSE (0.0292 ≤ SSE ≤ 0.0511) and ARE (0.8014 ≤ ARE ≤ 0.8822), equilibrium data agreed well with the Freundlich isotherm. The maximum adsorption capacity for Pb(II) and Zn(II) was determined to be 11.57 and 4.65 mg/g, respectively. Kinetic studies revealed that pseudo-second-order equation fitted well with the experimental data, which indicates that chemisorption is the rate-determining step of the adsorption system. Results have shown the possibility of GO as a potential adsorbent material in the treatment of soil washing wastewater.

This study presents levels of ¹³⁷Cs and ⁴⁰K concentrations in the placentas of seals gathered in the period 2007–2015. The mean activity of ¹³⁷Cs and ⁴⁰K was 5.49 Bq kg⁻¹w.w. and 136.6 Bq kg⁻¹ ww respectively. Statistically significant correlation was observed between the ¹³⁷Cs activities in placenta and in herring—the staple food for seals. The concentrations of ¹³⁷Cs and ⁴⁰K were also determined in other tissues (muscle, liver, lung, and brain) of wild seals. The concentrations of ¹³⁷Cs were from 2.59 Bq⁻¹ ww (lungs) to 24.3 Bq kg⁻¹ ww (muscles). The transfer factor values for ¹³⁷Cs (seal tissue/fish) ranged from 0.89 to 2.42 in the case of the placentas and from 1.35 to 8.17 in the case of the muscle. For adults seal, the effective dose from ¹³⁷Cs was 2.98 nGy h⁻¹. The mean external radiation dose to pup was 0.77 nGy h⁻¹ from ¹³⁷Cs and 6.69 nGy h⁻¹ from ⁴⁰K.

In this study, the novel adsorbent PVA-TA-βCD was synthesized via thermal cross-linking between polyvinyl alcohol and β-cyclodextrin. The characterization methods SEM-EDS, FTIR, and XPS were adopted to characterize the adsorbent. The effect of pH, contact time, initial concentrations, and temperature during the adsorption of Pb(II), Cd(II), and Mn(II) onto the PVA-TA-βCD was also investigated. In a single-component system, the data fitted well to pseudo-second-order, and film diffusion and intra-particle diffusion both played important roles in the adsorption process. As for isotherm study, it showed a heterogeneous adsorption capacity of 199.11, 116.52, and 90.28 mg g⁻¹ for the Pb(II), Cd(II), and Mn(II), respectively. Competition between the ions existed in a multi-component system; however, owing to the stronger affinity of the PVA-TA-βCD for Pb(II) relative to Cd(II) and Mn(II), the Pb(II) adsorption onto the PVA-TA-βCD was less affected by the addition of the other metals, which could be effectively explained by the hard and soft acid and base theory (HSAB). Furthermore, PVA-TA-βCD showed good reusability throughout regeneration experiments.

N₂O is a GHG of environmental concern. It is generated from the nitrous material contained in wastewater and is the sixth most important contributor to N₂O emissions. There is a great variety of methods to quantify the emission of N₂O in a wastewater treatment plant (WWTP), which present variants among them, such as predetermined values and operational data of the plants. In this paper, we compared three different methods to quantify the N₂O emission in 2015 from WWTP in two metropolitan areas with high population density: Mexico City and the Metropolitan Area of Barcelona (MAB). MAB has advanced treatment plants that remove nutrients from wastewater, and Mexico City has only traditional treatment plants. The N₂O emission/inhabitant from WWTPs in MAB (3,214,211 inhabitants served) was 40% lower than the plants in Mexico City (1,806,440 inhabitants served). The MAB emission was 0.009 tCO₂e/inhabitant and 0.013 tCO₂e/inhabitant in Mexico City; these emission values could be considered statistically different with a risk error of 5%. This difference could be due to the fact that MAB has nutrient removal (42% of inhabitants served), and Mexico City has only traditional treatment plants. The results obtained may be influenced by the default emission factors of each methodology. In addition, per capita protein consumption and water consumption per inhabitant are different parameters that must be considered between these zones to quantify and compare the emission of N₂O. The integral methods are closer to the reality of the N₂O emission when the operating parameters of each plant and wastewater are considered. There should be more research on the reduction of this GHG in wastewater treatment for a correct quantification of these emissions, and more especially in the estimation of N₂O emission factors suitable for each treatment plant and study area.

Evaluation of 50 nm zinc oxide nanoparticles’ (ZnO-NPs) effects on the microalgae Chlorococcum sp. growing in high salt growth medium (HSM) was investigated by using flow cytometry parameters (cell size (FSC), granularity (SSC), chlorophyll a fluorescence (FL3), and formation of reactive oxygen species (ROS)). Algal cells in exponential growth were exposed to 0–100 mg/L of ZnO-NPs and their physiological responses were measured after 24 and 96 h of treatment. Behavior of ZnO-NPs was analyzed in HSM and results indicated that ZnO-NPs formed agglomeration with a large distribution. Total soluble Zn concentration increased when initial ZnO-NP concentration increased. Significant negative effect on algal cells was observed after 96 h exposition and at high ZnO-NP concentration. This negative impact was evaluated by the significant increase in ROS production, inhibition in the photosynthetic electron transport, and reduction in cell growth. In this study, using flow cytometry multi-parameters might help to prevent and evaluate inhibitory effect of oxide nanoparticles on aquatic photosynthetic microorganisms.

This research project explores the performance of soils intended to support ornamental plants serving an ecological benefit within bioremediating rain gardens. Three plots of identical plantings were installed in autumn of 2015 into three different planting media in Northeast Ohio, USA. A control soil blend was tested against two experimental soil blends in the field under natural conditions for 3 years to explore any potential differences in overall plant performance. The control planting soil was created following current Ohio Department of Natural Resources specifications for rain garden planting soils which consist of no less than 80% sand and no more than 10% clay by volume. Test soil blends incorporated lightweight expanded shale to combat the potential negative effects of high sand soils for plants (i.e., high matric potential) while maintaining required engineering benefits (i.e., fast infiltration rate coupled with good physical, chemical, and biological filtration). Our analysis suggests that incorporating expanded shales into bioremediating gardens as a replacement to high sand content can maintain all engineering specifications and may increase survival rates of plant life beyond rates currently found in high sand content rain gardens. Survival rate for plants in the control plot was at 48.3% while experimental plots one and two were 96.5% and 75.8% respectively. The research team suggests that these increased survival rates could contribute to more widespread adoption and implementation of stormwater management practices, especially small-scale, interconnected rain gardens in the urban environment as designated by low-impact development standards.