Halogenated organics are widely used in modern industry, agriculture, and medicine, and their large-scale emissions have led to soil and water pollution. Electrochemical methods are attractive and promising techniques for wastewater treatment and have been developed for degradation of halogenated organic pollutants under mild conditions. Electrochemical techniques are classified according to main reaction pathways: (i) electrochemical reduction, in which cleavage of C-X (X = F, Cl, Br, I) bonds to release halide ions and produce non-halogenated and non-toxic organics and (ii) electrochemical oxidation, in which halogenated organics are degraded by electrogenerated oxidants. The electrode material is crucial to the degradation efficiency of an electrochemical process. Much research has therefore been devoted to developing appropriate electrode materials for practical applications. This paper reviews recent developments in electrode materials for electrochemical degradation of halogenated organics. And at the end of this paper, the characteristics of new combination methods, such as photocatalysis, nanofiltration, and the use of biochemical method, are discussed.

Elucidation of the interaction between NACs and smectites is important to the understanding of the potential for transport of nitroaromatic compounds (NACs) in soils and to implementation of NAC-contaminated soil remediation. The adsorption of dinitrotoluene isomers (DNTs) and substituted dinitrobenzenes (SDNBs) by smectite was determined by batch equilibration and characterized by FTIR and XPS, along with molecular dynamics simulations. The adsorption of DNTs differed substantially among the isomers, attributed to the overall degree of nitro deflection relative to the aromatic ring plane. The substituents in SDNBs strengthened the electrostatic interaction between smectite K⁺ and nitro groups, facilitating SDNB adsorption to smectite. The competition between 2,4-DNT and 1,3-DNB, as well as the inclusion complexation of K⁺ by crown ether 18c6e, both reduced 2,4-DNT adsorption to smectite by weakening the K⁺-nitro interaction. All the results demonstrated that the electrostatic interaction between smectite K⁺ and nitro of NACs was the predominant force in mediating their adsorption. This was supported by FTIR spectra that the N–O bands shifted due to the weakening of N–O bonds and strengthening of C–N bonds via the electron transfer to cations. The XPS of smectite further manifested the cation-nitro interactions that the binding energies of K 2p 1/2, K 2p 3/2, and Si 2p shifted higher with 1,3-DNB adsorbed. Molecular dynamics simulations indicated the aromatic planes of 2,4-DNP and 2,4-DNAs were parallel to the basal plane of smectite and the oxygens of nitro groups in the molecules were directly coordinated with smectite K⁺.

A novel magnetic attapulgite–biochar composite (MABC) derived from natural attapulgite, cauliflower leaves, and FeCl₃ was successfully prepared as a low-cost adsorbent for oxytetracycline (OTC) removal from aqueous solution. Characterization experiments by different techniques suggested that attapulgite clay particles and Fe₃O₄ nanoparticles were successfully covered on the MABC surface. Compared with the pristine biochar (CLB) and attapulgite–biochar composite (ABC), MABC had the largest surface area, well-developed pore structure, and more surface oxygen-containing functional groups which could interact with organic pollutant via hydrogen bonding, π–π electron coupling, complexation, and ion exchange. The maximum adsorption capacity of MABC by the Langmuir model was 33.31 mg/g, which was dramatically higher than that of CLB and ABC. The effects of solution initial pH had little difference on the adsorption of OTC because of the buffering effect. Adsorbent-regeneration studies of MABC exhibited good reusability and separation property. All the results indicated that MABC could be used as a potential adsorbent because of its easy preparation and separation, high efficiency, wide pH range application, and abundant and cheap raw materials in the global ecosystem. Graphical abstract

Cobalt (Co) is a nutrient for soil microorganisms and crops, as well as a worldwide industrial pollutant. When the level of Co exceeds the acceptable limit, this heavy metal can lead to devastating consequences for soil environments. There is considerable attention and concern about elevated levels of Co contaminating soil and crops. Spent mushroom substrate (SMS) is a potential amendment for the adsorption of pollutants, which has potential for resolving Co-polluted soil that spans the world. To investigate the environmental behavior and risks associated with Co in fluvo-aquic soil under specific treatments of SMS from Pleurotus ostreatus, a lab-scale pot experiment was conducted. SMS and exogenous Co were added to soil, which was retained for approximately 30 days. Pakchois (Brassica chinensis L.) were planted in the treated soil for 28 days until harvest. The Co speciation in soil (modified BCR sequential extraction) and Co accumulation in pakchoi tissue were studied. When the SMS concentration was within a range of 0 to 9 g kg⁻¹ (total amount = 0 to 2.7 g), Co in the acid-soluble fraction was transformed to the oxidizable fraction in soil, resulting from the mesh structure on the surface of SMS, as well as the amide and carboxyl in the SMS molecular structure. In this situation, the Co accumulation levels in the pakchois decreased significantly (P < 0.05), indicating the efficacy of SMS for reducing Co phytoavailability. However, when the SMS concentration reached 12 g kg⁻¹, the phytoavailability increased again (P < 0.05). When the SMS concentration ranged from 8.86 to 9.51 g kg⁻¹, the Co phytoavailability in soil reached a minimum, while the biomass of pakchoi reached a maximum. Conclusively, SMS from Pleurotus ostreatus are effective for reducing the Co phytoavailability, as well as for reducing the chance of Co transferring into a human’s body through crops (i.e., food consumption). In order to achieve the optimum efficacy, the SMS concentration in soil should be maintained at a range of 8.86 to 9.51 g kg⁻¹.

Tartrazine is one of the most widely used food additives. The present investigation was carried out on 40 adult male albino rats. They were divided into four groups of ten animals for each. Group I was considered as a control group. Group II was treated with tartrazine daily in a dose 7.5 mg/kg body weight by oral gavage for 30 days. Group III was received 15 mg/kg body weight of tartrazine for the same period. Group IV was administered tartrazine in a dose 100 mg/kg body weight for the whole duration of the experiment. At the end of experiment, samples from the cerebellum, submandibular salivary glands, and kidneys were fixed in neutral buffered formalin 10% and prepared routinely for paraffin sectioning and staining for histopathological and immunohistochemical investigations of proliferating cell nuclear antigen “PCNA” and glial fibrillar acidic protein “GFAP”. Tartrazine-treated groups revealed histopathological degenerative changes in the obtained organs. In group II, the cerebellum showed subcortical edema, congestion of the blood vessels, cytoplasmic vacuolations, and pyknosis of the nuclei in the gray matter neurons. Concerning the submandibular glands, they expressed cytoplasmic vacuolations and pyknosis of the nuclei of the acinar cells, congestion of the interacinar blood capillaries, and degenerative changes in the striated duct. The kidneys appeared with interstitial hemorrhage and dilatation of the glomerular capillaries. The PCT and DCT showed ill-defined cell boundaries. The collecting tubules in the renal medulla appeared with flattened epithelial cells. The severity of these changes increases by increasing the dose of tartrazine in group III and reach to the highest level in group IV. The immunoexpression of the GFAP in the cerebellum of the experimental groups was intense compared to the control group. The immunoreactivity of PCNA in the nuclei of the acinar and ductal cells of the submandibular gland and the cells of the renal cortex and medulla was strong in the tartrazine-treated groups compared to the control group. The current study concluded that the tartrazine had serious effect on the cerebellum, submandibular glands, and kidneys that adversely affect the functions of these organs.

The ambiguous mechanism that selenite seems to be absorbed by roots via phosphorus (P) and silicon (Si) transporters signifies P and Si may affect selenite uptake. However, the role of P and Si in phloem-mediated selenium (Se) transport within plant tissue is unknown. Therefore, in this work, tomato (Solanum lycopersicum L.) seedlings were exposed to selenite under different hydroponic conditions firstly. And then, split-root experiments were conducted. Results showed that Se uptake decreased as external pH increased. At pH 8, more selenite in the form of SeO₃²⁻ was assimilated under P-deficient conditions than under P-normal conditions. Silicate inhibited Se uptake only at pH 3 (27.5% H₂SeO₃ +72.5% HSeO₃⁻). The results of split-root experiments showed that Se concentrations in seedlings increased under heterogeneously high P or Si. Selenium transport from shoots to roots immersed in solution without selenite was also enhanced. This study illustrated that the affinity of tomato roots to assimilate selenite species followed the order of H₂SeO₃ >HSeO₃⁻ >SeO₃²⁻. H₂SeO₃ was absorbed into roots via Si transporters, whereas HSeO₃⁻ and a portion of SeO₃²⁻ were absorbed via low- and high-affinity P transporters, respectively. In addition, heterogeneously high P or Si concentrations in environmental media could enhance phloem-mediated Se redistribution.

The concepts of the cities we know nowadays, and which we are accustomed to, change at a very rapid pace. The philosophy of their design is also changing. It will base on new standards, entering a completely different, futuristic dimension. This stage is related to changes in the perception of space, location and lack of belonging to definite, national or cultural structures. Cities of the future are cities primarily intelligent, zero-energetic, zero-waste, environmentally sustainable, self-sufficient in terms of both organic food production and symbiosis between the environment and industry. New cities will be able to have new organisational structures—either city states, or, apolitical, jigsaw-like structures that can change their position—like in the case of the city of Artisanopolis, designed as a floating city, close to the land, reminiscent of the legendary Atlantis. This paper is focused on the main issues connected with problems of the contemporary city planning. The purpose of the research was to identify existing technological solutions, whose aim is to use solar energy and urban greenery. The studies were based on literature related to future city development issues and futuristic projects of the architects and city planners. In the paper, the following issues have been verified: futuristic cities and districts, and original bionic buildings, both residential and industrial. The results of the analysis have been presented in a tabular form.

Antibiotics, as one of the emerging pollutants, are non-biodegradable compounds and long-term exposure to them may affect endocrine, hormonal, and genetic systems of human beings, representing a potential risk for both the environment and human health. The presence of antibiotics in surface waters and drinking water causes a global health concern. Many researches have stated that conventional methods used for wastewater treatment cannot fully remove antibiotic residues, and they may be detected in receiving waters. It is reported that nanoparticles could remove these compounds even at low concentration and under varied conditions of pH. The current study aimed to review the most relevant publications reporting the use of different nanoparticles to remove antibiotics from aqueous solutions. Moreover, meta-analysis was conducted on the results of some articles. Results of meta-analysis proved that different nanoparticles could remove antibiotics with an acceptable efficiency of 61%. Finally, this review revealed that nanoparticles are promising and efficient materials for degradation and removal of antibiotics from water and wastewater solutions. Furthermore, future perspectives of the new generation nanostructure adsorbents were discussed in this study.

Poly-aluminium chloride (PAC) is often used to enhance phosphorus removal and control membrane fouling in membrane bioreactors (MBRs). However, the influence of aluminium accumulation on the biological nitrification and phosphorus removal of MBRs has not been well assessed. In the present study, the effects of accumulated aluminium on sludge activity and morphology were investigated in a lab-scale anoxic–oxic membrane bioreactor. The reasonably high removal efficiencies of NH₄⁺-N, TN, and COD, i.e. 94.9%, 84.8%, and 92.8%, respectively, were achieved in the reactor when the percentage of atomic aluminium on sludge surface increased to 14.2%. However, the decreases in the ammonia oxidation rate, nitrite oxidation rate, and specific oxygen uptake rate of sludge by 82.1%, 79.8%, and 46.4%, respectively, were observed. Meanwhile, the activity of phosphate-accumulating organisms was completely inhibited. Furthermore, the protein content in the extracellular polymeric substances of sludge decreased substantially, and the sludge became more dispersed due to the alum accumulation, compared with that of the initial phase. Therefore, long-term dosing of PAC in the MBR should be managed to avoid excessive aluminium accumulation in the sludge.

Photocrosslinked silicone acrylates are used in a variety of applications, such as printing inks, adhesives, or adhesive release liners. Their production requires the use of a photoinitiator. Even if the photoinitiator represents a minor mass in the photocurable formulation (2–10%), it is used in excess and residual amounts may therefore remain in the polymerized products and possibly migrate into the environment during the use of the products and/or at their end-of-life stage. Little is known on the possible degradation of silicone acrylate which may increase the potential release. The present study investigated the release of Darocur 1173, the most commonly used photoinitiator, from silicone matrix and the effect of accelerated photoageing on the extent of the phenomenon. Leaching tests in water were conducted on thin-coated plastic film (release liners) made of a mixture of polypropylene and polyethylene. Results showed that 44% of the Darocur 1173 photoinitiator initially used in silicone formulation was released from silicone matrix in the leaching test. Accelerated photoageing obtained by UV irradiation of the films for up to 200 h was found to favor photoinitiator degradation but also induced a strong and fast oxidation of silicone-coated liners as compared to that of uncoated ones. Graphical abstract