Progress and prospects of applying carbon-based materials (and nanomaterials) to accelerate anaerobic bioprocesses for the removal of micropollutants

Carbon-based materials (CBM), including activated carbon (AC), activated fibres (ACF), biochar (BC), nanotubes (CNT), carbon xenogels (CX) and graphene nanosheets (GNS), possess unique properties such as high surface area, sorption and catalytic characteristics, making them very versatile for many applications in environmental remediation. They are powerful redox mediators (RM) in anaerobic processes, accelerating the rates and extending the level of the reduction of pollutants and, consequently, affecting positively the global efficiency of their partial or total removal. The extraordinary conductive properties of CBM, and the possibility of tailoring their surface to address specific pollutants, make them promising as catalysts in the treatment of effluents containing diverse pollutants. CBM can be combined with magnetic nanoparticles (MNM) assembling catalytic and magnetic properties in a single composite (C@MNM), allowing their recovery and reuse after the treatment process. Furthermore, these composites have demonstrated extraordinary catalytic properties. Evaluation of the toxicological and environmental impact of direct and indirect exposure to nanomaterials is an important issue that must be considered when nanomaterials are applied. Though the chemical composition, size and physical characteristics may contribute to toxicological effects, the potential toxic impact of using CBM is not completely clear and is not always assessed. This review gives an overview of the current research on the application of CBM and C@MNM in bioremediation and on the possible environmental impact and toxicity.     

Developments in ultrasound--non-medical

Ultrasound is defined as sound of a frequency that is too high for the human ear to detect—i.e. it is inaudible. Nevertheless this “silent sound” has a large range of applications in science, medicine and industry. The study of the effects of ultrasound on materials—known as sonochemistry—is one of the broadest and most exciting areas in current research. In this review some recent developments with major potential are identified from the fields environmental protection and materials processing.

Environmental protection can refer to methods of preventing pollution or to the removal of existing pollution. Here we will look at examples drawn from the latter in which ultrasound has been used for the purification of water (chemical and biological), the decontamination of the atmosphere and soil remediation i.e. the classic three domains of water, air and land.

In terms of materials processing two examples have been chosen, the treatment of sewage sludge and the control of crystallisation. In both of these cases it is predominantly the mechanical effects of acoustic cavitation, which produce the enhanced digestion, and dewatering of sludge and provide for the control in crystallisation processes.     

人工纳米材料与生物膜相互作用机制及影响因素研究进展

人工纳米材料在水体中的环境行为与生物环境安全问题成为环境科学领域研究的热点,人工纳米材料与生物膜相互作用机制和影响因素是其中迫切需要研究解决的关键科学问题。本文主要探讨了人工纳米材料释放进入到水体中后对生物膜细菌活性、微生物群落结构、净污活性等的毒性效应,分析了人工纳米材料对生物膜的毒性作用机制及其影响因素,同时探讨了生物膜对人工纳米材料的吸附作用及机理,为深入研究人工纳米材料与生物膜的相互作用机制提供了重要的理论基础。     

Design of biomass-based renewable materials for environmental remediation

Various materials have been used to remove environmental contaminants for decades and have been an effective strategy for environmental cleanups. The current nonrenewable materials used for this purpose could impose secondary hazards and challenges in further downstream treatments. Biomass-based materials present viable, renewable, and sustainable solutions for environmental remediation. Recent biotechnology advances have developed biomaterials with new capacities, such as highly efficient biodegradation and treatment train integration. This review systemically discusses how biotechnology has empowered biomass-derived and bioinspired materials for environmental remediation sustainably and cost-effectively.     

Molecular simulation of carbon nanotubes as sorptive materials: sorption effects towards retene,perylene and cholesterol to 100 degrees Celsius and above

New water purification technologies are being developed as the world’s water sources are increasingly being polluted and experience a dramatic consumption with the increasing world population. In this context, the emerging era of nanotechnology has introduced a series of innovations and materials with promising potential as sorptive materials for water decontamination. The application of nanomaterials for the purification of ground/surface water introduces nevertheless a series of important challenges, such as health and safety, cost, process-efficiency and chemical sorption properties. In this study, we consider the latter class and present a study of the sorptive properties of carbon nanotubes (CNTs) as potential water decontaminating materials. Molecular dynamics simulations are used and three molecular candidates of the water contaminants, cholesterol, perylene and retene were selected for interaction study with CNTs at different diameters. The results show that CNTs form densely packed clusters with retene, perylene and cholesterol, binding each strongly to their tubular surfaces, as well as in their hollow tubular spaces. Cholesterol and perylene bind more strongly than retene, accounting for the calculated binding energies in vacuo, however the planar geometries of polycyclics may in general favour binding to CNTs over semi-polar molecules and can require further studies. Our studies show furthermore that the CNTs retain the adsorbed molecules also at 100 degrees Celsius, and require therefore additional steps of separation for eventual recycling and reusing the nanomaterials for additional decontamination. This study is important in providing data for initiating studies and developments of water purification approaches based on using CNTs.     

微生物对水环境污染物的趋化性研究进展

随着人类活动的干扰以及社会工业化进程的加剧,水环境污染现象日益严峻。微生物是水环境污染治理和修复的主要驱动者。越来越多的研究发现,水环境中污染物的去除速率与微生物的趋化功能密切相关。综述了近几年有关微生物对水环境中无机盐、溶解性有机物和重金属等的趋化特性研究进展,讨论并展望了基于趋化功能微生物精准调控的水环境污染强化治理技术的应用前景及主要问题。     

Life cycle assessment of emerging environmental technologies in the early stage of development: A case study on nanostructured materials

The use of nanostructured materials has been recently proposed in the field of environmental nanoremediation. This approach consists in using nanomaterials not directly, but as building blocks for the design of nano‐porous micro‐dimensional systems, overcoming the eco‐ and health‐toxicology risks generally associated with the use of nano‐sized technologies. Herein we report the use of life cycle assessment (LCA) as an eco‐design tool for optimizing the production of cellulose nanosponges (CNS), nanostructured materials recently developed for water remediation purposes. LCA was applied from the acquisition of raw materials to the synthesis of CNS (from cradle‐to‐gate), considering three production systems, from the lab‐level to a modeled scale‐up system. The lab‐scale LCA identified the main environmental hotspots, namely the energy‐consuming steps and the final purification of the material (washing step). In a second lab‐scale production, an improvement action could be implemented, switching the washing solvent from methanol to water and decreasing the washing temperature. A second LCA showed a reduced contribution to the impacts from the materials, while the global impacts remained within the same order of magnitude. A simulated scale‐up of the process allowed to optimize the energy‐consuming steps and the water consumption, through internal recycling. A third LCA assessed the resulting benefits and a decrease in the global impacts by two orders of magnitude. Our study contributes to the discussion of LCA community, providing a focus on the importance of scaling‐up of emerging technologies, namely nanostructured porous materials, highlighting the benefits of a LCA based approach since the very beginning of product design (eco‐design).     

Metallic nanoparticles: microbial synthesis and unique properties for biotechnological applications,bioavailability and biotransformation

The impact of nanotechnology in all areas of science and technology is evident. The expanding availability of a variety of nanostructures with properties in the nanometer size range has sparked widespread interest in their use in biotechnological systems, including the field of environmental remediation. Nanomaterials can be used as catalysts, adsorbents, membranes, water disinfectants and additives to increase catalytic activity and capability due to their high specific surface areas and nanosize effects. Thus, nanomaterials appear promising for new effective environmental technologies. Definitely, nanotechnology applications for site remediation and wastewater treatment are currently in research and development stages, and new innovations are underway. The synthesis of metallic nanoparticles has been intensively developed not only due to its fundamental scientific interest but also for many technological applications. The use of microorganisms in the synthesis of nanoparticles is a relatively new eco-friendly and promising area of research with considerable potential for expansion. On the other hand, chemical synthesis occurs generally under extreme conditions (e.g. pH, temperature) and also chemicals used may have associated environmental and human health impacts. This review is an overview of current research worldwide on the use of microorganisms during the biosynthesis of metallic nanoparticles and their unique properties that make them good candidates for many applications, including in biotechnology.     

Non-conventional low-cost adsorbents for dye removal: a review

Adsorption techniques are widely used to remove certain classes of pollutants from waters, especially those that are not easily biodegradable. Dyes represent one of the problematic groups. Currently, a combination of biological treatment and adsorption on activated carbon is becoming more common for removal of dyes from wastewater. Although commercial activated carbon is a preferred sorbent for color removal, its widespread use is restricted due to high cost. As such, alternative non-conventional sorbents have been investigated. It is well-known that natural materials, waste materials from industry and agriculture and biosorbents can be obtained and employed as inexpensive sorbents. In this review, an extensive list of sorbent literature has been compiled. The review (i) presents a critical analysis of these materials; (ii) describes their characteristics, advantages and limitations; and (iii) discusses various mechanisms involved. It is evident from a literature survey of about 210 recent papers that low-cost sorbents have demonstrated outstanding removal capabilities for certain dyes. In particular, chitosan might be a promising adsorbent for environmental and purification purposes.     

R&D priorities in the field of sustainable remediation and purification of agro-industrial and municipal wastewater

This article was presented as a position paper during the Environmental Biotechnology and Microbiology Conference in Bologna, Italy in April 2012. It indicates major and emerging environmental biotechnology research and development (R&D) priorities for EU members in the field of sustainable remediation and purification of agro-industrial and municipal wastewater. The identified priorities are: anaerobic/aerobic microbial treatment, combination of photochemical and biological treatment, phytoremediation and algae-based remediation, as well as innovative technologies currently investigated, such as enzyme-based treatment, bioelectrochemical treatment and recovery of nutrients and reuse of cleaned water. State of the art, research needs and prospective development in these domains are crucially discussed. As a result, goals of the future development of bioremediation and purification processes are defined and the way to achieve them is proposed.     

Potential for Plant-Based Remediation of Pesticide-Contaminated Soil and Water using Nontarget Plants such as Trees,Shrubs, and Grasses

Appropriate environmental management of pesticides includes their proper application, use of filter strips and riparian buffers to contain pesticides in runoff from fields, prompt cleanup of spills, and treatment processes for wastewater associated with manufacturing and equipment usage. Plants have beneficial effects in the management of pesticide-contaminated soil and water, including direct metabolism of many pesticides, stimulation of microbial activity in the root zone, extraction of contaminated water, and reduction of infiltrating contaminated water. In this work, we review the literature on nontarget plants that can grow in pesticide-contaminated soil and water, and the fate of pesticides in filter strips, riparian buffers, and vegetated remediation environments. Past research indicates that there are significant differences in the tolerance of plants to pesticides present in soil and water, and that some plants are more effective than others in the remediation of pesticide-contaminated soil and water. Thus, there is value in the identification of tolerant plants and favorable plant-based remediation technologies for management of pesticides and contaminated sites.     

Structure Design and Composition Engineering of Carbon‐Based Nanomaterials for Lithium Energy Storage

Carbon‐based nanomaterials have significantly pushed the boundary of electrochemical performance of lithium‐based batteries (LBs) thanks to their excellent conductivity, high specific surface area, controllable morphology, and intrinsic stability. Complementary to these inherent properties, various synthetic techniques have been adopted to prepare carbon‐based nanomaterials with diverse structures and different dimensionalities including 1D nanotubes and nanorods, 2D nanosheets and films, and 3D hierarchical architectures, which have been extensively applied as high‐performance electrode materials for energy storage and conversion. The present review aims to outline the structural design and composition engineering of carbon‐based nanomaterials as high‐performance electrodes of LBs including lithium‐ion batteries, lithium–sulfur batteries, and lithium–oxygen batteries. This review mainly focuses on the boosting of electrochemical performance of LBs by rational dimensional design and porous tailoring of advanced carbon‐based nanomaterials. Particular attention is also paid to integrating active materials into the carbon‐based nanomaterials, and the structure–performance relationship is also systematically discussed. The developmental trends and critical challenges in related fields are summarized, which may inspire more ideas for the design of advanced carbon‐based nanostructures with superior properties.     

Agricultural waste material as potential adsorbent for sequestering heavy metal ions from aqueous solutions - a review

Heavy metal remediation of aqueous streams is of special concern due to recalcitrant and persistency of heavy metals in environment. Conventional treatment technologies for the removal of these toxic heavy metals are not economical and further generate huge quantity of toxic chemical sludge. Biosorption is emerging as a potential alternative to the existing conventional technologies for the removal and/or recovery of metal ions from aqueous solutions. The major advantages of biosorption over conventional treatment methods include: low cost, high efficiency, minimization of chemical or biological sludge, regeneration of biosorbents and possibility of metal recovery. Cellulosic agricultural waste materials are an abundant source for significant metal biosorption. The functional groups present in agricultural waste biomass viz. acetamido, alcoholic, carbonyl, phenolic, amido, amino, sulphydryl groups etc. have affinity for heavy metal ions to form metal complexes or chelates. The mechanism of biosorption process includes chemisorption, complexation, adsorption on surface, diffusion through pores and ion exchange etc. The purpose of this review article is to provide the scattered available information on various aspects of utilization of the agricultural waste materials for heavy metal removal. Agricultural waste material being highly efficient, low cost and renewable source of biomass can be exploited for heavy metal remediation. Further these biosorbents can be modified for better efficiency and multiple reuses to enhance their applicability at industrial scale.     

An overview of phytoremediation as a potentially promising technology for environmental pollution control

Phytoremediation is the use of plants for the removal of pollutants from contaminated soil or water. Phytoremediation is an environmentally friendly and cost-effective alternative to current remediation technologies. This review article outlines general aspects of phytoremediation, along with discussions about its advantages and limitations. It further reviews various phytoremediation processes in detail: phytoextraction, rhizofiltration, phytostabilization, phytodegradation, and phytovolatilization. Unlike previous review articles available in various journals, this paper presents a more comprehensive view of this issue, and deals with a much wider range of its applications to environmental pollution control. These include the treatment of wastewaters, removal of heavy metals and metalloids (e.g. lead and arsenic), phytoremediation of organic pollutants, such as 2,4,6-trinitrotoluene (TNT) and polychlorinated biphenyls (PCBs), and cleanup of soil and water contaminated with radionuclides, such as cesium (¹³⁷Cs) and strontium (⁹⁰Sr). This paper also describes recent developments of transgenic plants for improving phytoremediation. Along the way, the present status of phytoremediation research in Korea is briefly introduced. Finally, the article concludes with suggestions for future research.     

Preparation and usage of nanomaterials in biomedicine

Nanotechnology is one of the most promising and decisive technologies in the world. Nanomaterials, as the primary research aspect of nanotechnology, are quite different from macroscopic materials because of their unique optical, electrical, magnetic, thermal properties, and more robust mechanical properties, which make them play an essential role in the field of materials science, biomedical field, aerospace field, and environmental energy. Different preparation methods for nanomaterials have various physical and chemical properties and are widely used in different areas. In this review, we focused on the preparation methods, including chemical, physical, and biological methods due to the properties of nanomaterials. We mainly clarified the characteristics, advantages, and disadvantages of different preparation methods. Then, we focused on the applications of nanomaterials in biomedicine, including biological detection, tumor diagnosis, and disease treatment, which provide a development trend and promising prospects for nanomaterials.     

工程纳米材料对污水生物处理影响的研究进展

工程纳米材料因其独特的物理化学性质被广泛应用于生产和生活中,但其潜在的风险正逐渐引起越来越多研究者的关注。目前国内外的研究主要探讨了工程纳米材料对模式微生物的毒性效应,但是对污水处理微生物的潜在影响尚缺乏系统和完整的报道。因此,本文综述了常见纳米材料对污水生物处理的影响,如碳、氮、磷的去除、甲烷化以及功能微生物种群结构演变等;同时还探讨了两种削减纳米银颗粒毒性的途径。综述内容为深入研究纳米材料对污水生物处理的潜在影响奠定了重要的理论基础。     

植物修复在抗生素污染治理中的应用研究进展

抗生素的环境污染问题日益严峻,如何对抗生素污染的水体和土壤进行有效的原位处理已然成为亟待解决的问题.植物修复是具有处理成本低、二次污染可控、易于后续处理、不破坏土壤和河流生态环境等优势的绿色、原位修复技术,已被证明是可用于抗生素污染治理的处理技术之一.因此,通过文献搜索和总结分析,作者们对植物修复在抗生素污染治理中的应...     

反硝化聚磷菌及其脱氮除磷机理研究进展

水体富营养化是当前水环境保护工作的重点关注问题,微生物修复富营养化水体具有高效、低耗且不产生二次污染等特点,已经成为富营养化水体生态修复的一种重要方式。近年来,对反硝化聚磷菌的研究及其在污水处理工艺中的应用越来越广泛。不同于传统的反硝化细菌联合聚磷菌去除氮磷工艺,反硝化聚磷菌在交替厌氧、缺氧/好氧条件下能同时进行脱氮除磷而被广泛关注与研究。值得注意的是,近几年报道的部分微生物仅在好氧条件下就可进行同时脱氮除磷,但是其脱氮除磷机理仍未理清。基于此,文中总结了目前发现的反硝化聚磷菌和同时硝化反硝化聚磷微生物的种类及特点,并对其脱氮与除磷的关系及其机理进行了系统性分析,对目前反硝化除磷存在的问题进行了梳理,最后对今后的研究方向进行了展望,以期为完善反硝化聚磷菌的脱氮除磷机理及工艺改进提供参考。     

水生植物-微生物联合去除水体有机污染物的研究进展

近年来,随着经济的快速发展,大量有机化合物随着工业废水和生活污水排放进入水体,严重破坏了水环境的生态平衡,威胁着水生生物及人类健康。植物-微生物联合修复技术因具有修复效率高、持续时间长、投入成本低,而且不会产生二次污染等特点,在水体有机污染治理中受到了人们的广泛关注。本文综述了近年来水生植物-微生物联合去除水体有机污染物的应用现状,详细阐述了水生植物-微生物联合修复过程中的研究方法、作用机制及影响因素。以期不断完善和优化水生植物-微生物联合修复技术,为实现水环境有机物污染的统筹高效治理提供参考。     

Cellulose-based virus-retentive filters: a review

Viral filtration is a critical step in the purification of biologics and in the monitoring of microbiological water quality. Viral filters are also essential protection elements against airborne viral particles. The present review first focuses on cellulose-based filter media currently used for size-exclusion and/or adsorptive filtration of viruses from biopharmaceutical and environmental water samples. Data from spiking studies quantifying the viral filtration performance of cellulosic filters are detailed, i.e., first, the virus reduction capacity of regenerated cellulose hollow fiber filters in the manufacturing process of blood products and, second, the efficiency of virus recovery/concentration from water samples by the viradel (virus adsorption–elution) method using charge modified, electropositive cellulosic filters or conventional electronegative cellulose ester microfilters. Viral analysis of field water samples by the viradel technique is also surveyed. This review then describes cellulose-based filter media used in individual protection equipment against airborne viral pathogens, presenting innovative filtration media with virucidal properties. Some pros and cons of cellulosic viral filters and perspectives for cellulose-based materials in viral filtration are underlined in the review.