Current synthesis routes of bismuth oxide nanosheets (BiONS) are relatively complicated, requiring the use of halogens or metalloids. Herein, a facile method to synthesize BiONS without the addition of halogens or other metalloids was developed. The synthesized BiONS were identified to have flake-shaped structures (300–1000 nm in width) with the thickness of 6–10 nm, which were predominantly made of β-Bi₂O₃. Such BiONS were applied to modify the surface of screen-printed carbon electrodes (BiONS-SPCEs) for the development of a robust palladium (Pd²⁺) sensor. After optimizing the electrochemical parameters of the sensor, it was found that the linear sensor response range and limit of detection for Pd²⁺ were 40–400 and 1.4 ppb, respectively. The electrocatalytic activity of the Pd²⁺-sensor was validated in the competing environment of other metal and metalloid ions. Real samples collected during a Pd recovery process from pharmaceutical wastewater were used to verify the application of BiONS-SPCEs in control of palladium recovery process. The quantitative results of post recovery palladium concentrations obtained using BiONS-SPCEs in treated pharmaceutical wastewater samples were in good agreement with those obtained by inductively coupled plasma-optical emission spectrometry (ICP-OES). Thus, such Pd²⁺-sensor provided the possibility of on-site process control of complex industrial samples for obtaining near-instant information that would lead to better management of resources used in the process, and same time assure environmental standards for both recovered products and processed discharge.

Continuous radon (222Rn) monitoring was conducted at two stations (site A and site B) with different perpendicular distance from the shoreline in Xiangshan Bay, East China Sea. Based on a 222Rn balance model (various sources and sinks of 222Rn in coastal water), the average rate of SGD was estimated to be 0.69cm/day and 0.23cm/day for site A and site B, respectively. The results from a nutrient analysis of the groundwater indicate that the associated nutrients fluxes loading through the SGD pathway were 4.27×106mol/day for DIN, 2.24×104mol/day for DIP and 1.82×106mol/day for DSi, respectively, which were comparable to or even higher than the levels observed in the local streams. Therefore, adequate attention should be paid to the importance of SGD as one source of nutrients during the eutrophication control process in this area.

Sequencing batch reactors (SBRs), due to its operational flexibility and excellent process control possibilities, are being extensively used for the treatment of wastewater which nowadays is fast becoming contaminated with newer and more complex pollutants. It is also possible to include different expanding array of configurations and various operational modifications to meet the effluent limits which are also continuously getting upgraded. This article provides basic description of SBR process along with its functional and physical variants that lead to improved the removal of nutrients and emerging contaminants. The significance of selectors and various recent advancements in the application of SBR has been discussed along with the possibilities held by SBR process in the treatment of wastewater of different origins and composition to produce effluent of reusable quality.

Increasingly severe environmental issues, especially those in developing countries such as China, drive the evolution of the environmental protection institution (EPI) to its strictest levels. However, the implementation of the strictest EPI still confronts various challenges and barriers, and the multi-stakeholder features of EPI determine these barriers are not independent of one another but rather present complex interactive relationships. This paper identifies the barriers to implementing China’s EPI from four aspects of environmental legal, economic, regulatory, and public participation institutions. A variable precision rough DEMATEL approach is proposed to visualize the causal relationships and intensities among barriers from the similarities and differences in perspectives of stakeholders from the government, company, and public levels. The obtained causal interactive mechanism among barriers highlights the need to prioritize the improvement of environmental policy assessment, and the concrete measures in policies or plans should be integrated into legislation to ensure they are mutually supportive early. The non-substantive contributions achieved by China’s public participation in environmental protection reveal prejudices that the public is often regarded as a supporter or spectator by both government and company groups, which makes the transparent environmental information disclosure, transfer and feedback into an effective mediation among stakeholders. Comprehensive coordination and feedback mechanisms including source prevention, process control, and severe punishment for consequences while enhancing linkages among stakeholders are put forward to overcome barriers and help implement the strictest EPI.

Economic and environmental stimuli for biodiesel production have also increased production of glycerol, a byproduct present in biodiesel industry wastewater (BIW). The objective of the present study was to analyze which factors influenced glycerol biodegradation in anaerobic sequencing batch reactors (AnSBR) in the attempt to optimize chemical oxygen demand (COD) removal efficiency. Six factors were analyzed: pH, temperature, mixing speed, influent COD, inoculum mass, and reaction time. The results indicated that mixing speed, temperature, mass of inoculum, and reaction time had direct influence on COD removal efficiency in BIW. The reactor used in the experiments operated with efficiencies and applied loads above those mentioned in the literature. The mathematical model generated in this study can be used for estimating efficiency, process control and scale up of AnSBR.

The present work explores the sorption capacity of an inexpensive and highly available agricultural waste, rice husk, to remove mercury using realistic concentrations of this metal. The efficiency of the process was evaluated for two initial Hg(II) concentrations, one representing the maximum value for Hg discharges from industrial sectors (0.05 mg L-1), and the other ten times higher. A very small amount of rice husk (0.25 and 0.50 g L-1) was able to reduce the Hg(II) levels in more than 80 % for an initial concentration of 0.05 mg L-1 and in more than 90 % for 0.50 mg L-1, corresponding to residual concentrations of Hg(II) of 0.048 and 0.009 mg L-1, respectively. The biosorvent was reused in further cleaning treatments, maintaining the efficiency and high performance. The sorption kinetics of the Hg-rice husk system is well fitted by the Elovich model and the diffusion models suggested that, depending on the initial Hg(II) concentrations, the sorption process can be controlled by intraparticle diffusion or by both film and intraparticle diffusion. The equilibrium data are well described by the linear isotherm and the distribution coefficient found was 36.1 L g-1. © 2013 Springer Science+Business Media Dordrecht.

Despite the importance of periphyton–metal interactions in bioremediation schemes and in phosphorus (P) cycling, the processes controlling metal accumulation in periphytic mats are still poorly understood. Iron (Fe) accumulation in periphytic mats was examined across a Fe settlement lagoon receiving mine drainage in Scotland, UK, between March and June 2008. Quantification and mapping of intracellular and extracellular Fe concentrations in periphyton samples using scanning electron microscopy–energy dispersive spectroscopy suggested that Fe accumulation was dominated by the association of Fe-rich precipitates with the extracellular polymeric substances matrix, rather than biotic uptake. Intracellular Fe concentrations were significantly higher in periphyton samples exposed to the highest dissolved Fe concentrations. Neither intracellular nor extracellular Fe concentrations were significantly affected by light availability or cell density. While diatoms dominated the periphyton communities there was no significant association of diatom functional groups with Fe accumulation, indicating that community composition may not affect the function of periphytic mats with respect to Fe removal. Scale-up calculations based on the mean measured Fe accumulation rate by periphyton substrates of 0.021 g m−2 day−1 showed that exposure of large surface areas of periphyton substrate in the settlement lagoon would only increase the Fe removal efficiency of the lagoon by c.1%.

To evaluate plant responses and compare metal uptake by different plants, several parameters and references have been used by researchers in the last few years. However, they express only the first-level comparison, i.e. biogeochemical comparison of different media (plant and soil) occurs in one place, at the same time and under the same circumstances. To integrate information about metal concentration in different media or plant organ and provide comparison of the process between control and treated cases, the second-level factors, the dynamic factors, are needed. Differently from the factors mentioned in the existing literature, they are able to show changes in processes under environmental changes rather than changes only in metal quantities. They are related both to internal (physiological) and external (ecological) factors. The paper introduces the use of dynamic factors for assessment of transfer and translocation of metals (Zn, Pb, Ni, Mn, Cu and Cr) in Scots pine (Pinus sylvestris L.), silver birch (Betula pendula) and black alder (Alnus glutinosa). Factor values and their implications are discussed in the paper.