Current Pollution Reports最新文献

Purpose of Review

The biochar-supported zero valent iron (ZVI-BC) can effectively prevent oxidation and agglomeration of ZVI, and improve the utilization rate of ZVI. Recent reviews of ZVI-BC mainly focus on the preparation methods, characterization techniques, and reaction mechanism with pollutants. Since the structural characteristics of biochar have a great impact on Fe⁰ loading, a comprehensive review of the structural characteristics of biochar is needed to explain its influence on ZVI formation during preparation. And in application of ZVI-BC, the environmental effects on organisms need to be considered. This review of recent research results provides a perspective for understanding the structural characteristics, preparation factors, and ecotoxicity of ZVI-BC.

Recent Findings

The adsorption capacity of ZVI-BC prepared by conventional methods still needs to be improved. The surface-area-normalized reaction rate constant (k_SA) of ZVI-BC can be increased to about 180 times by surface modification, adding a stabilizer, element doping, and other modification methods. Recent research on ecotoxicity has shown mostly positive effects of ZVI-BC on microorganisms, animals, and plants during environmental remediation.

Summary

This work reviews the effect of biochar as a support matrix on Fe⁰ production. The pollutant removal performance is summarized considering the elemental composition, phase components, and surface chemical properties. Also, we discuss the effect of ZVI-BC preparation on contaminant removal and propose methods to optimize the performance of ZVI-BC. The k_SA was used to conduct a meta-analysis of kinetic data to illustrate the properties of ZVI-BC. In addition, we evaluate the ecotoxicity of using ZVI-BC in environmental remediation.

Graphical Abstract

Purpose of Review

The purpose of this review is to summarize the current interactions between functional materials and microalgae, bacteria, and algal-bacterial symbioses in the environment, to analyze the mechanism of interaction between materials and the three, and to explore the development potential of functional materials in the application of algal-bacterial symbioses for better pollutant removal.

Recent Findings

Algal-bacterial symbioses were a more promising means of wastewater treatment, but the efficiency of the treatment needed to be enhanced. Pollutant removal relies mainly on oxidative decomposition nutrient uptake by algal-bacterial symbioses. Some functional materials enhanced the biomass of microalgae by supplementing them with trace elements for growth, regulating their photosynthesis (material conversion spectrum, light capture, and carbon sequestration), stimulating their metabolism, enhancing pigment accumulation, and lipid accumulation, thus indirectly removing pollutants. In addition, the hybrids formed by bacteria and light-absorbing materials were used in the algal-bacterial symbioses via performing artificial photosynthesis for indirect pollutant removal. Thus, the combination of materials with microalgae and bacteria has broader application prospects.

Summary

The introduction of functional materials increased the efficiency of algal-bacterial symbioses in treating pollutants, which was mainly facilitated by increasing microalgal biomass to convert pollutants to algal-bacterial symbioses. This paper reviewed the research process of algal-bacterial symbioses for pollutants treatment and investigated the reaction mechanism of materials with microalgae, bacteria, and algal-bacterial symbioses, respectively. Overall, this review focuses on the development trend of functional materials in algal-bacterial symbioses and provides a reference for their application in algal-bacterial symbiotic system for wastewater treatment.

Socio-economic and environmental factors have led scientific community to find alternative approaches for management of agro-industrial wastes. An integrated approach, i.e., clean biotechnology, could be used for the conversion of agro-industrial wastes into industrial important and less toxic end products. Bacterial cellulose (BC) is an incredibly multifaceted biomaterial with desirable attributes including biodegradability, biocompatibility, great tensile strength, cellulose purity, and porosity. An economical BC production is difficult to owing to the cost of expensive synthetic media. By utilizing processed agro-industrial wastes as media substrate, a sustainable large-scale BC production can be achieved along with an effective waste management strategy. Various types of industrial wastes including crop residues, food industry by-products, distillery effluents, and kitchen wastes are used to produce BC. This review is centered on various aspects of cost-effective BC production using industrial wastes and a wide range of probable substrates with alternative methods for enhanced BC production. Novel applications involving BC in the field of environment, wound healing, drug delivery, dental treatment, etc., with an emphasis on new economic opportunities are also discussed. Overall, this study suggests that integrating different methods and techno-economic analysis would be advantageous to researchers in finding way for sustainable production of BC with reduced environmental pollution for diverse applications.

Purpose of Review

Heavy and toxic metals are becoming more prevalent in the water sources of the globe, which has detrimental repercussions for both human health and the health of ecosystems. The summary of recent findings on treatment possibilities of toxic metal species by nanomaterials should facilitate the development of more advanced techniques of their removal.

Recent Findings

The high concentrations of chromium, mercury, and arsenic identified in wastewater cause a hazard to human health. There is a wide variety of nanoadsorbents and nanophotocatalysts used for heavy/hazardous metal removal. Recent research has resulted in the production of advanced nanostructures that exhibit extraordinary heavy/hazardous metal adsorption effectiveness and photocatalytic diminution of metal ions. These nanostructures have physically and chemically tunable features.

Summary

In this review article, the use of carbon-based nanomaterials, polymer-based nanomaterials, and semiconductor-based nanomaterials are extensively discussed to remove mercury, chromium, and arsenic ions from wastewater by the adsorption process. Advanced nanomaterials involved in photocatalytic reduction are also comprehensively discussed.

Purpose of Review

Free-flowing rivers act as conduits for sediment and nutrient transport from the land to coastal oceans. In the past decades, many of global rivers have been dammed for water resource management. The associated ecological impacts have become a wide concern, and have been intensively studied. In this work, we aim to review the research progress of the topic on sediment and nutrient trapping by river dams using CiteSpace, summarize the findings of previous literatures, and propose perspectives for future studies.

Recent Findings

We found that (i) this topic has been continuously concerned and the publication number has been increasing annually. In 2006–2021, there are 1385 publications in total, including 1318 articles and 23 reviews; (ii) dams can interrupt river connectivity and trap sediment and nutrients in reservoirs, greatly deceasing sediment and nutrient loads to coastal oceans; (iii) sediment and nutrient trapping by dams has caused a series of ecological impacts, including reservoir capacity loss, river channel erosion, river delta land loss, reservoir eutrophication, and massive greenhouse gas emissions.

Summary

This review summarized the changes of riverine sediment and nutrient loads caused by dams, and their impacts on river ecosystems. The following aspects should be concerned in future studies: the impacts of biogeochemical cycling within reservoirs on the stoichiometry and bioavailability of nutrients in dam discharge, the net greenhouse gas emissions caused by dams, and the cumulative impacts of cascade dams. It adds our comprehensive understanding of sediment and nutrient trapping by river dams and will be beneficial to future studies in this field.

Purpose of Review

Advanced oxidation processes (AOPs) are proven effective in degrading recalcitrant pollutants in wastewater. Numerous researchers have been targeting advanced catalytic materials to further promote AOP efficiency. Recent studies indicated the great catalytic activity of FeOCl in AOP systems, inducing the prevailing research on the modification and application of the FeOCl-based layer-structure materials. This review summarizes the progress in existing works of FeOCl as AOP catalysts and provides challenging perspectives for future work.

Recent Findings

FeOCl shows outstanding catalytic performance in conventional Fenton and other AOP systems, such as Fenton-like, photo-activated and electro-activated processes. Nevertheless, FeOCl catalytic efficiency in AOPs still demands improvement owing to the relatively low effective surface area of bulk-phase FeOCl, slow regeneration of active Fe (II) from Fe (III), prone leaching of iron ions, and difficulty in recycling or long-term functioning. Consequently, various modification approaches, including intercalation, exfoliation, combination, and membrane-fabrication, have been adopted to effectively promote pollutant removal efficiency in different FeOCl-catalyzed AOP systems.

Summary

This review presents the promising application of FeOCl as catalysts in AOPs and multiple modification methods successfully applied to FeOCl for catalytic performance improvement. Moreover, some remaining gaps in FeOCl preparation, purity determination, stability control, complex water matrix effects, and mechanism illustration are summarized, hopefully providing viable viewpoints for future research on AOP water treatment practices.

Graphical Abstract

Schematic illustration of FeOCl and its modified products in AOPs for water treatment.

Purpose of Review

Extreme weather including heat waves, droughts, and extreme precipitation can impact the microbiological risks of drinking water in complex and comprehensive ways. These impacts are especially concerned with coastal cities due to the higher frequency and intensity of extreme weather. This review was aimed at summarizing these impacts from the view of different parts of drinking water systems including water sources, drinking water treatment plants (DWTPs), and drinking water distribution systems (DWDSs).

Recent Findings

All extreme weather will pose microbiological threats to drinking water quality. However, the threats are realized in direct or indirect ways. In the former, the extreme weather itself can alter the microbial biomass, growth rate, activity, and tolerance. In the latter, it will first change the physicochemical water parameters and/or the performance of the water treatment processes and then impact microbes. Meantime, extreme weather can result in the induction, occurrence, and removal of emerging microbiological contaminants, thus making the situation more complicated.

Summary

This review summarized the potential impacts of extreme weather on microbiological risks of drinking water in coastal cities. It also analyzed the interactive relationship between extreme weather and microbes. However, many knowledge gaps remained for this issue. The occurrence, transportation, control, and removal mechanism/methods of microbial contaminants under the background of climate change should be further investigated.

Graphical Abstract

Purpose of Review

Microalgae-mediated resource recovery and recycling of wastewater might be useful in producing biomass, biofertilizers, and environmentally acceptable bioproducts. This review aims to provide a comprehensive understanding of the challenges and opportunities of wastewater valorization to valuable algal biomass by opting a self-sustainable carbon-neutral approach.

Recent Findings

Various challenges and opportunities of using unsterilized urban wastewater are explored to provide insights into addressing the processing issues. Major wastewater challenges include turbidity with blackish appearance, emerging contaminants, pathogenic microbial community, and higher nutrient load. A brief comparison of sterilization techniques has been made, mainly focusing on principles, advantages, and limitations. Despite the challenges, it is found that microalgae-based resource recovery could be a viable and promising opportunity in a wastewater-driven integrated biorefinery paradigm.

Summary

Despite the availability of various wastewater treatment methods, microalgae-based wastewater treatment is promising, and carbon neutral approach which transforms the nutrients to valuable biomass, thereby reducing the nutrient load of the water. However, microalgal cultivation in wastewater encounters physical and biological challenges. In this article, challenges, opportunities, and sterilization methods of wastewater are critically reviewed concerning microalgae-based resource recovery from the urban wastewater. The processing of wastewater-produced algal biomass could be valorized into multiple products in minimal waste and carbon-neutral paradigm.

Graphical Abstract

The textile, paper and pulp, distillery, and pharmaceutical industries are only a few of the many sectors that contribute significantly to the contamination of water bodies and their unsuitability for human use. Pharmaceuticals, which are credited with saving millions of lives in recent decades, have emerged as a new category of environmental hazard. Their prolonged presence in the environment has a number of negative effects, including gene toxicity, hormone interference, antibiotic resistance, the imposition of sex organs, and many others. To ensure that everyone in the world can access to uncontaminated and safe drinking water, it is important to treat pharmaceutical laden wastewater before discharge in fresh water body. Nanotechnology is getting significant attention due to enormous properties such as the high surface area to volume ratio, new optical properties, and desired shape. Nanomaterials might be a strong option for purifying water of a variety of environmental pollutants. This review also touches on several environmental aspects of pharmaceuticals, including (i) the current status of pharmaceuticals production and their use pattern, (ii) sources, occurrence, and transport behaviour of pharmaceuticals, (iii) analysis techniques and potential toxicity of pharmaceuticals and (iv) various conventional and advanced nanotechnology for water remediation. The present review is predominately designed to highlight the progress and major update in advantaged nanotechnology for remediation of pharmaceutical contaminated wastewater. The literature study (2015–2022) critically illustrated the recent pharmaceutical contaminations concerns and remediation efforts emphasizing nanotechnology like nanoadsorption, AOPs, nano-catalyst, electrochemical degradation and nanomembrane/nanofiltration technology.