Food security is a high-priority issue for sustainable global development both quantitatively and qualitatively. In recent decades, adverse effects of unexpected contaminants on crop quality have ...threatened both food security and human health. Heavy metals and metalloids (e.g., Hg, As, Pb, Cd, and Cr) can disturb human metabolomics, contributing to morbidity and even mortality. Therefore, this review focuses on and describes heavy metal contamination in soil–food crop subsystems with respect to human health risks. It also explores the possible geographical pathways of heavy metals in such subsystems. In-depth discussion is further offered on physiological/molecular translocation mechanisms involved in the uptake of metallic contaminants inside food crops. Finally, management strategies are proposed to regain sustainability in soil–food subsystems.
•Heavy metal pollution has perturbed the environment to pose serious health hazards.•Therefore, the diverse and emerging issues of food security have become a global concern.•A better understanding on the soil-food crop transfer mechanisms is prerequisite for remediation.•This review provides a general view on the global geographical pattern of heavy metal sources.•The review discusses state-of-the-art remediation approaches to manage soil metal pollution.
In recent years, many of micropollutants have been widely detected because of continuous input of pharmaceuticals and personal care products (PPCPs) into the environment and newly developed ...state-of-the-art analytical methods. PPCP residues are frequently detected in drinking water sources, sewage treatment plants (STPs), and water treatment plants (WTPs) due to their universal consumption, low human metabolic capability, and improper disposal. When partially metabolized PPCPs are transferred into STPs, they elicit negative effects on biological treatment processes; therefore, conventional STPs are insufficient when it comes to PPCP removal. Furthermore, the excreted metabolites may become secondary pollutants and can be further modified in receiving water bodies. Several advanced treatment systems, including membrane filtration, granular activated carbon, and advanced oxidation processes, have been used for the effective removal of individual PPCPs. This review covers the occurrence patterns of PPCPs in water environments and the techniques adopted for their treatment in STP/WTP unit processes operating in various countries. The aim of this review is to provide a comprehensive summary of the removal and fate of PPCPs in different treatment facilities as well as the optimum methods for their elimination in STP and WTP systems.
•There is a large variation in PPCP removal in STPs and WTPs (−157–100%).•PPCP removal is dependent on compound characteristics and process-specific factors.•Advanced treatment technologies are effective for PPCP removal.
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Metal organic frameworks (MOFs) have been investigated extensively for separation, storage, catalysis, and sensing applications. Nonetheless, problems associated with their toxicity, ...recycling/reuse/regeneration, and degradation have yet to be addressed as one criterion to satisfy their commercialization. Here, the challenges associated with MOF-based technology have been explored to further expand their practical utility in various applications. We start a brief description of challenges associated with MOF-based technology followed by a critical evaluation of toxicity and need of technical options for regeneration of MOFs. Importantly, diverse techniques/process for reuse and regeneration of MOFs like activation of MOFs by heat, vacuum, solvent exchange, supercritical carbon dioxide (SCCO2) and other miscellaneous options have been discussed with recent examples. Afterward, we also present an economical aspect and future perspectives of MOFs for real world applications. All in all, we aimed to present opportunities and critical review of the current status of MOF technology with respect to their recycling/reuse/regeneration to consider their environmental impact.
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•Metal-organic frameworks (MOFs) are extensive polymeric crystalline materials.•The synthesis and applications of MOFs have been hot topics in academic and industrial research.•Here, the toxicity, recycling/reuse/regeneration, and degradation of MOFs are explored in various respects.•The needs for MOF recycling are assessed in relation to sustainable waste management.•Conclusions are drawn to highlight the opportunities and challenges in related fields of MOF research.
•Crossed effects among H2S and NH3 on the performance of a biotrickling filter were investigated.•Excellent removal efficiencies of H2S (98.5%) and NH3 (99.9%) were obtained.•NH3 significantly ...affected the composition of by-products of sulphide oxidation.•High SO42− concentration further enhanced NH3 removal.•<9.9s was required to treat H2S and NH3 up to 500ppm without pH control.
A coal slag-packed biotrickling filter inoculated with autotrophic sulphide oxidizing and ammonia oxidizing bacteria was successfully operated for co-treating hydrogen sulphide (H2S) and ammonia (NH3). Excellent removal efficiencies of H2S (98.5%) and NH3 (99.9%) were obtained at loadings of up to 120g H2Sm−3h−1 and 80g NH3m−3h−1, respectively. The inhibitory effects of selected pollutants and metabolic products on the treatment performance were evaluated through mass balance and bacterial community analyses. The presence of NH3 significantly affected the composition of metabolic products of sulphide oxidation. Elemental sulphur was the dominant metabolite that ranged from 35% to 65%, whereas the amount of sulphite and thiosulphate generally increased up to 20%. However, a similar trend in the distribution of by-products to the results of nitrogen mass balance from sole NH3 removal was observed. The predominant bacteria were also changed with different loading ratios (H2S:NH3).
The tremendous amount of food waste from diverse sources is an environmental burden if disposed of inappropriately. Thus, implementation of a biorefinery platform for food waste is an ideal option to ...pursue (e.g., production of value-added products while reducing the volume of waste). The adoption of such a process is expected to reduce the production cost of biodegradable plastics (e.g., compared to conventional routes of production using overpriced pure substrates (e.g., glucose)). This review focuses on current technologies for the production of polyhydroxyalkanoates (PHA) from food waste. Technical details were also described to offer clear insights into diverse pretreatments for preparation of raw materials for the actual production of bioplastic (from food wastes). In this respect, particular attention was paid to fermentation technologies based on pure and mixed cultures. A clear description on the chemical modification of starch, cellulose, chitin, and caprolactone is also provided with a number of case studies (covering PHA-based products) along with a discussion on the prospects of food waste valorization approaches and their economic/technical viability.
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•The tremendous amount of food waste (FW) is produced from diverse sources.•To resolve FW problems, implementation of a biorefinery platform for FW is essential.•The adoption of such a process can produce value-added products while reducing the waste.•This review focuses on current technologies for the production of polyhydroxyalkanoates (PHA).•Prospects of FW valorization are discussed along with their economic/technical viability.
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•Co-disposal of red mud and lignin via the thermo-chemical process.•Sustainable thermo-chemical process using CO2 as reaction media.•Fabrication of biochar composite with red mud and ...lignin.•Valorization of biochar composite for using a reduction catalyst.
The massive generation of red mud has been considered as a serious environmental burden because of its toxicity, alkaline nature, and complex compositional matrix. Accordingly, diverse technical approaches for red mud utilization have been extensively developed, but their practical implementation has not been fully established because of technical incompleteness. In these respects, establishing reliable strategies for disposing red mud is of great importance. To enhance the technical viability of red mud valorisation, utilizing an existing disposal platform for solid wastes can be an alternative option. Therefore, co-pyrolysis of red mud and lignin was conducted in this study. Furthermore, the possible utilization of CO2 during the co-pyrolysis was explored to valorise the end-product (biochar), which enhanced its porosity. In addition to the enhanced porosity, CO2 utilization during the co-pyrolysis of red mud and lignin led to surplus generation of CO by shifting the carbon distribution from pyrolytic oil to CO. In detail, CO generation in the CO2 environment was enhanced 24 times more than that in the N2 environment. Thus, the surplus CO in the CO2 environment was used to transform iron oxides in the red mud into zero-valent iron. In sum, two functionalities (enhanced porosity and zero-valent iron content) were leveraged by the CO2, which synergistically enhanced the reduction capability of the biochar. Reduction of p-nitrophenol and Cr(VI) was successfully completed using biochar, of which removal efficiency by reduction reached up to 99 and 69.7%, respectively. Therefore, the experimental findings provide a breakthrough for valorising two widespread waste materials, red mud and lignin.
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•Analyzed the occurrence and fate of antibiotics both in a wastewater treatment plant and the receiving water.•Removal of quinolones is mainly ascribed to sludge ...adsorption.•Sulfonamides hardly adsorbed onto the sludge.•Reinforcing the regulation and treatment of aquaculture sewage is necessary.
Wastewater treatment plants (WWTPs) are not designed for the removal of antibiotics. Thus, several studies have been conducted to evaluate the fate of antibiotics in wastewater treatment processes. However, most of these investigations did not consider the antibiotic contamination in the receiving waters. This study investigated the occurrence and fate of antibiotics in a wastewater treatment plant and the ecological risks posed by surface water receiving the effluent discharge. The results indicated that the levels of 18 antibiotics in the influent ranged from 37.21ngL−1 to 2935.40ngL−1, and sulfamethizole (SMZ) was the major component among the 18 antibiotics; SMZ occurred most frequently and at the highest concentrations. Mass balance analysis was performed to explore the mechanisms of antibiotic removal, and the findings indicated that biotic and abiotic degradation are the major removal mechanisms; however, removal of quinolones is primarily ascribed to sludge adsorption. Because activated sludge consists of negatively charged colloidal particles, it is more inclined to adsorb quinolones, which contain positively charged nitrogen atoms. The resulting loading of antibiotics from WWTP effluent discharge into the receiving water of the Yangjie River may result in their uptake by aquatic organisms and thus poses a risk to human health.
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•Graphene based materials (GBMs) have been accessed for the removal of gaseous VOCs.•Synthesis and structural importance (as adsorbent) of GBMs are described.•GBMs are effective ...adsorbents for both polar and non-polar VOCs.•The performance of GBMS has been assessed based on key performance metrics.
In recent years, graphene-based materials (GBMs) have been regarded as the core technology in diverse research fields. Consequently, the demand for large-scale synthesis of GBMs has been increasing continuously for various fields of industry. These materials have become a competitive adsorbent for the removal of environmental pollutants with improved adsorption capacity and cost effectiveness through hybridization or fabrication of various functionalities on their large surface. In particular, their applicability opens up new avenues for the adsorptive removal of volatile organic compounds (VOCs) (e.g., through the build-up of efficient air purification systems). This review explored the basic knowledge and synthesis approaches for GBMs and their performances as adsorbent for VOC removal. Moreover, the mechanisms associated with the VOC removal were explained in detail. The performance of GBMs has also been evaluated along with their present limitations and future perspectives.
Few studies have explored the successive impacts of plant litter composition on soil microbial structure and function, litter decomposition patterns and final soil carbon sequestration. In this ...study, two dominant halophytes in the Jiuduansha Wetland of the Yangtze River estuary, Phragmites communis and Spartina alterniflora, were selected for in-situ and ex-situ decomposition experiments aiming to clarify the difference in decomposition rate of their litter types in soil. Furthermore, plant litter composition, soil organic carbon and humus contents, soil respiration, microbial respiration and soil microbial structure were analyzed to explore dominant decomposition patterns of the two types of litter in soil and their organic carbon sequestration capability, as well as the microbiological mechanisms involved. The S. alterniflora litter decomposed faster in soil than P. communis due to its lower contents of cellulose and lignin. More degradable carbon in S. alterniflora litter induced higher proportions of the microbial community responsible for mineralization in the soil, such as classes β-Proteobacteria and γ-Proteobacteria and genera Geobacter and Flavobacterium, leading to higher soil respiration. Consequently, despite the S. alterniflora zone having higher aboveground plant biomass than the P. communis zone, there were lower contents of soil organic carbon and humus. The P. communis zone, in contrast, on account of the induced higher proportion of a specific microbial community, such as class Anaerolineae and genera Methylibium, Gallionella and Desulfococcus – which potentially weakened mineralization and accelerated humification – resulted in lower soil respiration and thus higher contents of soil organic carbon and humus. These indicated that plant biomass was not the only factor affecting the soil organic carbon content; plant litter composition was also an important factor because it induced different soil microbial community structures which led to different organic carbon decomposition patterns, and therefore different soil organic carbon sequestration capability.
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•S. alterniflora with less recalcitrant compound decays faster than P. communis.•Litter quality selects microorganisms leading to different C decomposition potential.•Litter quality originally but indirectly affected its decomposition pattern in soil.•Plants can be converted to more humus is true high C-sequestration plants for soil.
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