General phases in the plan and implementation of an environmental remediation of radioactively contaminated sites are planning for remediation, site characterization, remediation criteria, remediation strategy, implementing remediation actions, and conducting post-remediation activities. Environmental remediation should commence with a planning stage. It is helpful to prepare reports which detail all the supporting activities related to these elements before significant levels of funds and efforts are committed. Site characterization is needed to provide sufficient data to make strategic decisions on the environmental remediation activities. The source characterization should include both waste characterization and facility or site characterization and should provide reliable estimates of the release rates of radioactive constituents as well as constituent distribution. During the preliminary site characterization, an engineering study should be conducted to develop remediation options which address the specific contaminant problem and are aimed to reduce radiological and chemical exposure. Options will include engineering approaches and associated technologies. A preliminary selection of options may be made based on several factors including future sites use, technical considerations, public acceptability, cost, and regulatory requirements. The implementation of remediation actions includes procurement of the selected technology, preparation of the site, development of a health and safety plan, development of operations procedures, staff selection and training, completion of site cleanup, verification, waste disposal, and release of the site for any future use. Once remediation activities have been completed and verified, the remediated site can be released for restricted or unrestricted use. Remediation of radioactively contaminated sites may require special adaptation to address sites covering very large surface areas or those which are deep and difficult to access. Quality assurance may be very important to the verification of environmental remediation activities. The selection of optimal remediation technologies to solve or mitigate the safety of an environmental contamination problem should be taken into account several factors. The several factors include performance (the ability of the technology to reduce risk to the health and safety of the public and to the environment), reliability and maintenance requirements for the technology, costs of implementing the technology, infrastructure available to support the technology, availability(the ease of accessing the technology and associated services), risk to workers and public safety, environmental impacts of the technology, ability of the technology to meet regulatory acceptance, and communication of stakeholder.

The need for high-performance environmental remediation has increased due to the environment’s ongoing degradation in the form of significant growth in industrialization and urbanization. Therefore, the toxic heavy metals can easily enter into environmental as well as foods and thus the search of clean water for drinking, household and irrigation purposes is of crucial importance. To meet this challenge, microelectrodes are flexible, low-cost and easier for fabrication has become the strong role in the detection of heavy metals with high sensitivity towards higher adsorption of heavy metals from contaminated water. To improve the sensitivity of the microelectrodes, carbon-based microelectrodes decorated with nanomaterials have been explored for the detection of metal ions thereby their presence in trace levels can be estimated. The aim of the present review is to summarize the recent developments in carbon-based microelectrodes for the electrochemical determination of heavy metals. It is followed by the various nanomaterials decorated on the carbon microelectrodes for detection of heavy metals was systematically discussed. Finally, the application and the future perspectives in the development of smart electrochemical sensing is provided. This short review will provide the useful information for the recent development in microelectrodes and also guide the pathway for the detection of heavy metals.

The ability to both assay the presence of, and to selectively remove ions in a solution is an important tool for waste water treatment in many industrial sectors, especially the nuclear industry. Nuclear waste streams contain high concentrations of heavy metals ions and radionuclides, which are extremely toxic and harmful to the environment, wildlife and humans. For the UK nuclear industry alone, it is estimated that there will be 4.9 million metric tonnes of radioactive waste by 2125, which contains a significant number of toxic radionuclides and heavy metals. This is exacerbated further by increased international growth of nuclear new build and decommissioning. Efforts to remove radionuclides have been focused on the development and optimisation of current separation and sequestering techniques as well as new technologies. Due to the large volumes of waste the techniques must be economical, simple to use and highly efficient in application. Magnetic nanoparticles (MNPs) offer a powerful enhancement of normal ion exchange materials in that they can be navigated to specific places using external magnetic fields and hence can be used to investigate challenges such as, pipework in preparation of decommissioning projects. They also have the potential to be fine-tuned to extract a variety of other radionuclides and toxic heavy metals. It has been demonstrated that with the right functional groups these particles become very strongly selective to radionuclides, such as Uranium. However, this new technology also has the potential to effectively aid nuclear waste remediation at a low cost for the separation of both radionuclides and heavy metals. In this work, we investigate the origin of the selectivity of superparamagnetic iron oxide nanoparticles (SPIONs) to Uranium by making systematic changes to the existing surface chemistry and determining how these changes influence the selectivity. Identifying the mechanism by which selected common nuclear related metals, such as Na(I), K(I), Cs(I), Ca(II), Cu(II), Co(II), Ni(II), Cd(II), Mg(II), Sr(II), Pb(II), Al(III), Mn(II), Eu(III) and Fe(III), are sorbed will allow for specific NP-target (nanoparticle) ion interactions to be revealed. Ultimately this understanding will provide guidance in the design of new targeted NP-ligand constructs for other environmental systems.

Oil spills into ocean or coastal waters can result in significant damage to the environment via pollution of aquatic ecosystems. Absorbents based on reduced graphene oxide (rGO) foams have the capacity to remove minor or major oil spills. However, conventional chemical synthesis of rGO often uses petrochemical precursors, potentially harmful chemicals, and requires special processing conditions that are expensive to maintain. In this work, an alternative cost-effective and environmentally friendly approach suitable for large-scale production of high-quality rGO directly from used cooking sunflower oil is discussed. Thus, produced flaky graphene structures are effective in absorbing used commercial sunflower oil and engine oil, via monolayer physisorption in the case of used sunflower and engine oils facilitated by van der Waals forces, π–π stacking and hydrophobic interactions, π-cation ( H+) stacking and radical scavenging activities. From adsorption kinetic models, first-order kinetics provides a better fit for used sunflower oil adsorption (R2 = 0.9919) and second-order kinetics provides a better fit for engine oil adsorption (R2 = 0.9823). From intra-particle diffusion model, R2 for USO is 0.9788 and EO is 0.9851, which indicates that both used sunflower and engine oils adsorption processes follow an intra-particle diffusion mechanism. This study confirms that waste-derived rGO could be used for environmental remediation.

점토광물은 자연에서 쉽게 얻을 수 있고, 환경친화적이며 다양한 물리화학적 특성을 갖고 있어 인류 역사상 여러 분야에 활용되어 왔다. 최근에는 몬모릴로나이트, 카올리나이트, 세피올라이트, 금 속이중층수산화물과 같은 점토 화합물에 화학적 개질을 도입하여 산업분야에 활용하고자 하는 연구 가 활발히 진행되고 있다. 넓은 비표면적과 높은 측면비율, 나노수준의 입자 두께, 그리고 조절가능한 표면전하를 갖는 점토화합물에 화학적 개질을 적용하면, 고분자의 기계적 성질과 기체차단성을 개선 하고, 고분자 필름에 지속적 항균성을 부여하는 충전제로 사용할 수 있다. 또한, 개질된 점토화합물은 높은 흡착능과 화학적 선택성을 지니므로, 수질이나 토양을 오염시키는 화학적, 생물학적 오염원을 효 과적으로 제거하는 물질로도 활용 가능하다. 본 논평에서는 이러한 점토화합물들이 미래의 주요산업 군인 식품포장재 및 환경개선 분야에 활용될 가능성에 대해 최근 연구 결과를 소개하고자 한다.