The present experimental study reports the performance of tea waste (TW) derived adsorbent for the adsorption of sodium diclofenac (SD) from aqueous solution (SD concentration = 10–50 mg/L). The waste-derived activated carbon was prepared by chemical activation process of raw waste using H₂SO₄, KOH, ZnCl₂, and K₂CO₃ as activating agents (TW: activating agent = 1:1 by weight). Subsequently, the oven-dried material was carbonized at 600-°C temperature for 2 h. The synthesized adsorbents were porous and their Brunauer-Emmett-Teller (BET) surface area was ranged 115–865 m²/g. Among all synthesized adsorbents, the adsorbent activated by ZnCl₂ exhibited the highest adsorption capacity (= 62 mg/g), though it was much lower compared to 91 mg/g obtained with commercial activated carbon (CAC) (SD concentration = 30 mg/L, adsorbent dose = 300 mg/L and initial wastewater pH = 6.47). SD equilibrium data could be described by Langmuir isotherm adequately, while pseudo-second-order rate model showed better fit to the time based adsorption data. Low activation energy of the adsorption process suggests the reaction to be temperature independent. Thermodynamic parameters showed the spontaneous and endothermic nature of adsorption process conducted in the presence of waste derived adsorbent.

Impacts of red beet consumption both on human and animal health are subject of intense research. In particular, products that are not heat-processed contain plethora of bioactive compounds that hold promise against numerous degenerative and aging-associated diseases. However, high level of nitrates (typically more than 2 g NO₃⁻ kg⁻¹) whose health effects are perceived with reasoned objections counterbalance these benefits. Following the above, from a certain level, the increased consumption of red beet has contrary impacts, creating a limiting factor not only from the economic point of view but also in terms of beneficial compounds intake. Reduction of NO₃⁻ levels (− 35%) has been achieved by soil amendment via increased doses of biochar. The data obtained indicates that the mechanism can be explained as follows. The soil improvement reduces soil density, increases soil temperature, improves water retention, and other prerequisites for increased activity of soil microorganisms. Accelerated metabolism of soil biota turned more nitrogen from fertilizers into organic forms. Hence, less mineral nitrogen is left for red beet intake.

Spatial and temporal distributions of tropospheric NO₂ vertical column densities over Pakistan during the period 2002–2014 are discussed. Data products from three satellite instruments SCIAMACHY, OMI, and GOME-2 are used to prepare a database of tropospheric NO₂ column densities over Pakistan and temporal evolution is also determined. Plausible NO₂ sources in Pakistan are also discussed. The results show a large NO₂ growth over all provinces and the major cities of Pakistan except the megacity of Karachi. Decline in industrial activities due to energy crises, worsening law and order situation, terrorist attacks, and political instability was explored as the main factor for lower NO₂ VCDs over Karachi City. The overall increase can be attributed to the anthropogenic emissions over the areas with high population, traffic density, and industrial activities. Source identification revealed that use of fossil fuels by various sectors including power generation, vehicles, and residential sectors along with agriculture fires are among significant sources of NO₂ emissions in Pakistan. Existing emission inventories such as EDGARv4.2 and MACCity largely underestimate the true anthropogenic NOₓ emissions in Pakistan. This study may provide vital information to policy makers and regulatory authorities in developing countries, including Pakistan, in order to devise effective air pollution abatement policies.

Common hazelnuts are widely present in human diet all over the world, and their beneficial effects on the health have been extensively investigated and demonstrated. Different in-depth researches have highlighted that the harvesting area can define small variations in the chemical composition of the fruits, affecting their quality. As a consequence, it has become relevant to develop methodologies which would allow authenticating and tracing hazelnuts. In the light of this, the present work aims to develop a non-destructive method for the authentication of a specific high-quality Italian hazelnut, “Nocciola Romana,” registered with a protected designation of origin (PDO). Thus, different samples of this fruit have been analyzed by near-infrared (NIR) spectroscopy and then classification models have been built, in order to distinguish between the PDO fruits and the hazelnuts not coming from the designated region. In particular, two different classification approaches have been tested, a discriminant one, partial least squares-discriminant analysis, and a class-modeling one, soft independent modeling of class analogies. Both methods led to very high prediction capability in external validation on a test set (classification accuracy in one case, and sensitivity and specificity in the other, all higher than 92%), suggesting that the proposed methodologies are suitable for a rapid and non-destructive authentication of the product.

Low methane (CH₄) emission reduction efficiency (< 25%) has been prevalent due to inefficient biological exhaust gas treatment facilities in mechanic biological waste treatment plants (MBTs) in Germany. This study aimed to quantify the improved capacity of biofilters composed of a mixture of organic (pine bark) and inorganic (expanded clay) packing materials in reducing CH₄ emissions in both a lab-scale experiment and field-scale implementation. CH₄ removal performance was evaluated using lab-scale biofilter columns under varied inflow CH₄ concentrations (70, 130, and 200 g m⁻³) and corresponding loading rates of 8.2, 4.76, and 3.81 g m⁻³ h⁻¹, respectively. The laboratory CH₄ removal rates (1.2–2.2 g m⁻³ h⁻¹) showed positive correlation with the inflow CH₄ loading rates (4–8.2 g m⁻³ h⁻¹), indicating high potential for field-scale implementation. Three field-scale biofilter systems with the proposed mixture packing materials were constructed in an MBT in Neumünster, northern Germany. A relatively stable CH₄ removal efficiency of 38–50% was observed under varied inflow CH₄ concentrations of 28–39 g m⁻³ (loading rates of 1120–2340 g m⁻³ h⁻¹) over a 24-h period. The CH₄ removal rate was approximately 500–700 g m⁻³ h⁻¹, which was significantly higher than relevant previously reported field-scale biofilter systems (16–50 g m⁻³ h⁻¹). The present study provides a promising configuration of biofilter systems composed of a mixture of organic (pine bark) and inorganic (expanded clay) packing materials to achieve high CH₄ emission reduction. Graphic abstract ᅟ

The advanced treatment of municipal secondary effluent by heterogeneous and homogeneous Fenton processes using Fe/Ce-RGO (reduced graphene oxide) and Fe²⁺ as catalysts was studied and compared. Sulfamethazine (SMT) was spiked in the effluent to examine the effectiveness of the emerging contaminant removal. The Fe/Ce-RGO catalyst was characterized using a scanning electron microscope (SEM) and cycle voltammetry curves. The removal of dissolved organic carbon (DOC), soluble chemical oxygen demand (SCOD), SMT, and ultraviolet-visible spectroscopy in 254 nm (UV₂₅₄) of municipal secondary effluents was examined. The DOC removal efficiency of secondary effluent (without addition of SMT) was 36.30% and 11.74% using Fe/Ce-RGO and Fe²⁺ as catalysts, respectively. The removal efficiency of DOC, SCOD, and SMT in heterogeneous Fenton process was higher than that in homogeneous Fenton process. The changes of three-dimensional excitation-emission matrix (3DEEM) fluorescence, soluble microbial products (SMPs), humic acids, and UV₂₅₄ were determined, and the results indicated that UV₂₅₄, aromatic proteins, and humic acids decreased rapidly in both processes; however, polysaccharides and protein-like substances were difficult to degrade. Although some toxic substances produced after Fenton-like treatment, the biodegradability of the treated effluent was enhanced.

The response of giant reed (Arundo donax L.) to selenium (Se), added as selenate, was studied. The development, stress response, uptake, translocation, and accumulation of Se were documented in three giant reed ecotypes STM (Hungary), BL (USA), and ESP (Spain), representing different climatic zones. Plantlets regenerated from sterile tissue cultures were grown under greenhouse conditions in sand supplemented with 0, 2.5, 5, and 10 mg Se kg⁻¹ added as sodium selenate. Total Se content was measured in different plant parts using hydride generation atomic fluorescence spectroscopy. All plants developed normally in the 0–5.0 mg Se kg⁻¹ concentration range regardless of ecotype, but no growth occurred at 10.0 mg Se kg⁻¹. There were no signs of chlorosis or necrosis, and the photosynthetic machinery was not affected as evidenced by no marked differences in the structure of thylakoid membranes. There was no change in the maximum quantum yield of photosystem II (Fᵥ/Fₘ ratio) in the three ecotypes under Se stress, except for a significant negative effect in the ESP ecotype in the 5.0 mg Se kg⁻¹ treatment. Glutathione peroxidase (GPx) activity increased as the Se concentration increased in the growth medium. GPx activity was higher in the shoot system than the root system in all Se treatments. All ecotypes showed great capacity of take up, translocate and accumulate selenium in their stem and leaf. Relative Se accumulation is best described as leaf ˃˃ stem ˃ root. The ESP ecotype accumulated 1783 μg g⁻¹ in leaf, followed by BL with 1769 μg g⁻¹, and STM with 1606 μg g⁻¹ in the 5.0 mg Se kg⁻¹ treatment. All ecotypes showed high values of translocation and bioaccumulation factors, particularly the ESP ecotype (10.1 and 689, respectively, at the highest tolerated Se supplementation level). Based on these findings, Arundo donax has been identified as the first monocot hyperaccumulator of selenium, because Se concentration in the leaves of all three ecotypes, and also in the stem of the ESP ecotype, is higher than 0.1% (dry weight basis) under the conditions tested. Tolerance up to 5.0 mg Se kg⁻¹ and the Se hyperaccumulation capacity make giant reed a promising tool for Se phytoremediation.

Nanoscale zero-valent iron (nZVI), with its reductive potentials and wide availability, offers degradative remediation for environmental pollutants. However, weaknesses such as easy aggregation, easy oxidation, and nanoscale size have hindered its further applications in the environment to some extent. Therefore, various supported nZVI composites (SNCs) with higher dispersibility, enhanced water stability, and tunable size have been developed to overcome the weaknesses. SNCs family is a great alternative for water purification applications that require high removal efficiency and rapid kinetics, as a result of their multifunctional properties and magnetic separation capacity. In this review, we compare the advantages of SNCs to nZVI for pollutant removal in water, discuss for the first time the synthetic techniques of obtaining SNCs, and analyze the influencing factors and mechanisms associated with the removal of some typical hazardous pollutants (e.g., dyes, heavy metals, nitrogen, and phosphorus) using SNCs. Moreover, limitations and future research needs of such material are discussed. More attention should be paid to the evaluation of toxicity, development of green synthetic routes, and potential application areas of such materials in future research.

This comparative field study examined the responses of bacterial community structure and diversity to the revegetation of zinc (Zn) smelting waste slag with eight plant species after 5 years. The microbial community structure of waste slag with and without vegetation was evaluated using high-throughput sequencing. The physiochemical properties of Zn smelting slag after revegetation with eight plant rhizospheres for 5 years were improved compared to those of bulk slag. Revegetation significantly increased the microbial community diversity in plant rhizospheres, and at the phylum level, Proteobacteria, Acidobacteria, and Bacteroidetes were notably more abundant in rhizosphere slags than those in bulk waste slag. Additionally, revegetation increased the relative abundance of plant growth-promoting rhizobacteria such as Flavobacterium, Streptomyces, and Arthrobacter as well as symbiotic N₂ fixers such as Bradyrhizobium. Three dominant native plant species (Arundo donax, Broussonetia papyrifera, and Robinia pseudoacacia) greatly increased the quality of the rhizosphere slags. Canonical correspondence analysis showed that the differences in bacterial community structure between the bulk and rhizosphere slags were explained by slag properties, i.e., pH, available copper (Cu) and lead (Pb), moisture, available nitrogen (N), phosphorus (P), and potassium (K), and organic matter (OM); however, available Zn and cadmium (Cd) contents were the slag parameters that best explained the differences between the rhizosphere communities of the eight plant species. The results suggested that revegetation plays an important role in enhancing bacterial community abundance and diversity in rhizosphere slags and that revegetation may also regulate microbiological properties and diversity mainly through changes in heavy metal bioavailability and physiochemical slag characteristics.

This study examines the complex relationship between decentralization, national context and environment policy performance with the cross-sectional data from 118 countries. Decentralization is decomposed into three dimensions: political, fiscal and administrative. Both multiple regression analysis and fuzzy set qualitative comparative analysis are adopted. Results show that: (1) political, fiscal and administrative decentralization differ in their impacts on environmental policy performance. (2) There are multiple pathways, constituted by specific configurations of decentralization and context conditions, to high (or low) environmental policy performance. (3) High environmental policy performance occurs most often when a country is fiscally and administratively decentralized and its context is favorable, i.e. advanced economy, good governance and stringent environmental regulations. In this situation, political decentralization seems to be irrelevant to the outcome. (4) Low environmental policy performance occurs most often when a country, without the favorable context mentioned above, become fiscally centralized, regardless of whether political and administrative decentralization is present or not. This study suggests policy makers should keep in mind the contextual fit of decentralization and adopt a configurational thinking in environmental governance.