Comparative effects of biochar-nanosheets and conventional organic-amendments on health risks abatement of potentially toxic elements via consumption of wheat grown on industrially contaminated-soil

Potentially toxic elements (PTEs) discharge to the soil environment through increased anthropogenic activities is a global threat. These l'Its can have harmful and chronic-persistent health effects on exposed populations through food consumption grown on contaminated soils. Efforts to investigate the transformation mechanism and accumulation behavior of PTEs in soil-plant system and their adverse health effects have focused extensively in previous studies. However, limited studies address biochar nano sheets (BCNs) as a potential soil amendment to reduced humans health risks through dietary intake of food-crop grown on PTE-contaminated soil. Here, we showed how BCNs cutback health hazards of PTEs through impacts on bioavailability and phytoaccumulation of PTEs, and their daily intake via consumption of wheat. When BCNs amendment was compared with both conventional organic amendments (COAs) and control, it significantly (P <= 0.05) reduced bioavailability and uptake of PTEs by wheat plants. Based on risk assessment results, the hazard indices (HIs) for PTEs in all treatments were <1, however, BCNs addition significantly (P <= 0.05) reduced risk level, when compared to control. Furthermore, the cancer risks for Cd, Cr and Ni over a lifetime of exposure were higher in all treatments than the tolerable limit (1.00E-4 to 1.00E-6), however BCNs addition significantly suppressed cancer risk compared to control. Conclusively, our results suggest that BCNs can be used as soil amendment to reduce potential risks of PTEs through consumption of food grown in PTE-contaminated soils. (C) 2017 Elsevier Ltd. All rights reserved

Operating conditions-induced changes in product yield and characteristics during thermal-conversion of peanut shell to biochar in relation to economic analysis

The influences of pyrolysis conditions on the products yield distribution and physico-chemical characteristics of biochar derived from peanut shell in a fixed-bed reactor were investigated in this study. The pyrolysis conditions included the pyrolysis temperature (300-700 degrees C), retention time (15-90 min), heating rate (1-10 degrees C min(-1)), gas flow rate (20-200 mL min(-1)) and feedstock particle size (<0.075, 0.075 0.150, 0.150-0.300 and 0.300-2.00 mm). Various analytical techniques were used to characterize the biochar for ultimate and proximate analyses, higher heating value (23.99-30.44 MJ kg(-1)), pH (8.11 -12.89), electrical conductivity (22.78-34.44 mS cm(-1)), surface functional groups (acidic, carboxylic and basic groups), Fourier transform infrared spectroscopy analysis, pore volume (0.055-1.241 cm(3) g(-1)) and specific surface area (7.12-20.96 m(2) g(-1)). The results demonstrated that the temperature predominantly regulated the product yields distribution and characteristics of produced biochar. Furthermore, the heating rate considerably influenced the biochar proximate composition, micropore surface area and pore size. Particle size had significant influences on biochar surface porosity and bio-oil yield. The economic analysis of the pyrolysis system indicated its feasibility and superiority with a positive net present value of 12.07 x 10(6) USD after twenty-five years of operation. (C) 2018 Elsevier Ltd. All rights reserved

Novel investigation of pyrolysis mechanisms and kinetics for functional groups in biomass matrix

Biomass, as a renewable and sustainable energy resource, can be converted into environmentally friendly and practically valuable biofuels and chemical materials via pyrolysis. However, the process optimization and pyrolysis efficiency are restricted by the limited perception of the complicated mechanisms and kinetics for biomass pyrolysis. Here, to establish an in-depth mechanism model for biomass pyrolysis, we presented a novel investigation for the thermal evolutions and pyrolysis kinetics of the functional groups in peanut shell matrix by using in-situ Fourier transform infrared spectrometry (in-situ FTIR) and thermogravimetric analysis-Fourier transform infrared spectrometry-mass spectrometry (TG-FTIR-MS). The in-situ FTIR spectrum deconvolution for the solid matrix was innovatively introduced to identify and quantify the real-time evolution and thermal dynamics of the functional groups during peanut shell pyrolysis. The result for the first time proposed that the pyrolysis mechanisms of total OH at 20-380 degrees C, aliphatic C-H-n groups at 20-500 degrees C, C=O groups at 260-500 degrees C, and C-O groups at 300-500 degrees C were dominant by diffusion and order-based chemical reactions. The TG-FTIR-MS analysis was conducted for the online monitoring of the released volatiles and gases, the amounts of which were in the sequence of C=O > CO2 > aliphatic C-O-(H) > C-O-(C) in esters > aromatics > H2O > phenolic hydroxyl > aliphatic hydrocarbons > CO. The study established a novel methodology to evaluate the biomass pyrolysis mechanisms at the molecular level, which provided valuable information for developing advanced pyrolysis techniques on a large scale for sustainable ecosystem

Recent advances in carbon-based renewable adsorbent for selective carbon dioxide capture and separation-A review

In terms of net intensification in the greenhouse effect ie., rise of global temperature which has triggered melting of glacier thus increasing sea level and acidification of sea, carbon dioxide alone contributes approximately three-fourth of the net greenhouse radiative forcing by man-made (anthropogenic) greenhouse gases emissions. Carbon dioxide capture and storage (CCS) technology; a promising strategy for capturing of carbon dioxide from point sources before its release to atmosphere by using various sorbents is gaining global interest. In this study, the established carbon capture technologies with methods of carbon dioxide separation along there pros and cons are discussed. Carbon-based adsorbents are considered as the most versatile adsorbents for carbon dioxide due to their extraordinary physical and chemical properties. In this manuscript, recent developments on carbonaceous adsorbents (biochar, activated carbons, and graphene-based adsorbents) and their role in carbon dioxide capture during different combustion processes and conditions have been comprehensively focused. (C) 2019 Elsevier Ltd. All rights reserved

In-situ oxidative degradation of sulfamethoxazole by calcium peroxide/persulfate dual oxidant system in water and soil

Calcium peroxide (CaO₂) and persulfate (PS) dual oxidant system is an innovative in-situ chemical oxidation (ISCO) technique for the restoration of contaminated groundwater. Several field applications also confirm its efficacy in remediating the groundwater, however, published articles are rarely present. In this work, the performance of the CaO₂/PS system was examined for the degradation of sulfamethoxazole (SMX) in the SMX polluted soil and water. Results indicated that SMX could be efficiently degraded with CaO₂ and PS (2 g/L dosages for each oxidant) around neutral pH (7), and 95.8% pollutant removed after 36 h of reaction time. The removal efficiency of SMX improved as the concentrations of CaO₂ and PS were increased. Moreover, SMX removal was significantly decreased with the increase of initial solution pH. This dual oxidant system at 30 °C was also used for the remediation of SMX (10 mg/kg) spiked soil. Soil degradation experiment was performed at 150 rpm of shaking speed using soil slurry (soil/water; 1/1 ratio) at pH 7. Dual oxidant dosage was kept at 2 g/L CaO₂ and 2 g/L PS. The results showed that this dual oxidant system is also very efficient for the antibiotics SMX degradation in the soil system. Overall, an insight knowledge and practical information gained from this work will help in the treatment of SMX contaminated soil and water as well as wastewater with CaO₂/PS dual oxidant system

A comprehensive review of biogeochemical distribution and fractionation of lead isotopes for source tracing in distinct interactive environmental compartments

Lead (Pb) is a non-essential and extremely noxious metallic-element whose biogeochemical cycle has been influenced predominantly by increasing human activities to a great extent. The introduction and enrichment of this ubiquitous contaminant in the terrestrial-environment has a long history and getting more attention due to its adverse health effects to living organisms even at very low exposure levels. Its lethal-effects can vary widely depending on the atmospheric-depositions, fates and distribution of Pb isotopes (i.e., Pb-204, Pb-206 & Pb-208) in the terrestrial-environment. Thus, it is essential to understand the depositional behavior and transformation mechanism of Pb and the factors affecting Pb isotopes composition in the terrestrial-compartments. Owing to the persistence nature of Pb-isotopic fractions, regardless of ongoing biogeochemical-processes taking place in soils and in other interlinked terrestrial-compartments of the biosphere makes Pb isotope ratios (Pb-IRs) more recognizable as a powerful and an efficient-tool for tracing the source(s) and helped uncover pertinent migration and transformation processes. This review discusses the ongoing developments in tracing migration pathway and distribution of lead in various terrestrial-compartments and investigates the processes regulating the Pb isotope geochemistry taking into account the source identification of lead, its transformation among miscellaneous terrestrial-compartments and detoxification mechanism in soil-plant system. Additionally, this compendium reveals that Pb-pools in various terrestrial-compartments differ in Pb isotopic fractionations. In order to improve understanding of partition behaviors and biogeochemical pathways of Pb isotope in terrestrial environment future works should involve investigation of changes in Pb isotopic compositions during weathering processes and atmospheric-biological sub-cycles. (C) 2019 Elsevier B.V. All rights reserved

Investigating the biochar effects on C-mineralization and sequestration of carbon in soil compared with conventional amendments using the stable isotope (delta C-13) approach

Biomass-derived black carbon (biochar) is considered to be an effective tool to mitigate global warming by long-term C-sequestration in soil and to influence C-mineralization via priming effects. However, the underlying mechanism of biochar (BC) priming relative to conventional biowaste (BW) amendments remains uncertain. Here, we used a stable carbon isotope (delta C-13) approach to estimate the possible biochar effects on native soil C-mineralization compared with various BW additions and potential carbon sequestration. The results show that immediately after application, BC suppresses and then increases C-mineralization, causing a loss of 0.14-7.17 mg-CO2-C g(-1)-C compared to the control (0.24-1.86 mg-CO2-C g(-1)-C) over 1-120 days. Negative priming was observed for BC compared to various BW amendments (-10.22 to -23.56 mg-CO2-C g(-1)-soil-C); however, it was trivially positive relative to that of the control (8.64 mg-CO2-C g(-1)-soil-C). Furthermore, according to the residual carbon and delta C-13 signature of postexperimental soil carbon, BC-C significantly increased (P < 0.05) the soil carbon stock by carbon sequestration in soil compared with various biowaste amendments. The results of cumulative CO2-C emissions, relative priming effects, and carbon storage indicate that BC reduces C-mineralization, resulting in greater C-sequestration compared with other BW amendments, and the magnitude of this effect initially increases and then decreases and stabilizes over time, possibly due to the presence of recalcitrant-C (4.92 mg-C g(-1)-soil) in BC, the reduced microbial activity, and the sorption of labile organic carbon (OC) onto BC particles

Enrichment and distribution of trace elements in Padhrar, Thar and Kotli coals from Pakistan: Comparison to coals from China with an emphasis on the elements distribution

This paper reports the mineralogical and geochemical compositions of the Padhrar (salt-range), Thar (Block Nos. 3 and 5) and Kotli coals. The coal investigated in this study is lignite to sub-bituminous coal, with a broad range of ash yields, volatile matter content and sulfur contents. The mineralogical characteristic, major and trace elements were determined by X-ray diffraction, inductively coupled plasma-atomic emission spectrometry and inductively coupled plasma-mass spectrometry, respectively. The mineral assemblages, sulfur contents, ash yields, and (CaO + MgO + Fe2O3)/(SiO2+ Al2O3) ratio varied significantly in the coal, which is attributed mainly to variation in the depositional environment. Pyritic sulfur is the main form of sulfur in the coals from Padhrar, Kotli and Thar coalfield. The minerals in the studied coals are dominated by quartz, pyrite, kaolinite, illite, along with calcite, feldspar, siderite, montmorillonite and gypsum. Sixteen trace elements, including Li, Be, B, Ti, Sc, V, Cr, Mn, Co, Ni, Cu, Zn, As, Rb, Sr, and Ba and five major elements P, Ca, Al, Fe, and Si, were investigated in this study. The trace element concentrations show variety within the coal seams in the Thar coals and the affinities vary among locations. The concentration of Sr, Ti, Zn, Li, Ni, Cu, Sc, As, Be, and B in the present study are within the range of average Chinese coal values, with the exception of V, Cr, Fe, P, and Rb. On the other hand, compared with world coals, the studied coals have higher contents of B, Cr, Li, Fe, V, Rb, P, and Sc. Based on statistical analyses, most of the trace elements, show an affinity to ash yield and possible association with pyrite, kaolinite, and calcite

Effects of biochar on uptake, acquisition and translocation of silver nanoparticles in rice (Oryza sativa L.) in relation to growth, photosynthetic traits and nutrients displacement

Rapid development in nanotechnology and incorporation of silver nanoparticles (AgNPs) in wide range of consumer products causing the considerable release of these NPs in the environment, leading concerns for ecosystem safety and plant health. In this study, rice (Oryza sativa) was exposed to AgNPs (0, 100, 200, 500 and 1000 mg L-1) in biochar amended (2 %w/v) and un-amended systems. Exposure of plants to AgNPs alone reduced the root and shoot length, biomass production, chlorophyll contents, photosynthesis related physiological parameters as well as macro-and micronutrients in a dose dependent manner. However, in case of biochar amendment, physiological parameters i.e., net photosynthesis rate, maximum photosynthesis rate, CO2 assimilation, dark respiration and stomatal conductance reduced only 16, 6, 7, 3 and 8%, respectively under AgNPs exposure at 1000 mg L-1 dose. Meanwhile, biochar at all exposure level of AgNPs decreased the bioaccumulation of Ag in rice root and shoot tissues, thus alleviated the phyto-toxic effects of NPs on plant growth. Moreover, results showed that biochar reduced the bioavailability of AgNPs by surface complexation, suppressing dissolution and release of toxic Ag+ ions in the growth medium. The presence of biochar at least decreased 2-fold tissue contents of Ag even at highest AgNPs (1000 mg L-1) concentration. These finding suggested that biochar derived from waste biomass resources can be used effectively to prevent the bioaccumulation and subsequent trophic level transfer of emerging Ag nano-pollutant in the environment. (C) 2019 Elsevier Ltd. All rights reserved

Environmental transformation and nano-toxicity of engineered nano-particles (ENPs) in aquatic and terrestrial organisms

The rapid development in nanotechnology and incorporation of engineered nano-particles (ENPs) in a wide range of consumer products releasing the massive quantities of ENPs in different environmental compartments. The released ENPs from nano-enabled products during their life cycle raising environmental health and safety issues. This review addresses the recent state of knowledge regarding the ENPs ecotoxicity to various organisms lying at different trophic levels. Studies show that reactive oxygen species (ROS) mediated oxidative stress is the primary mechanism of nano-toxicity, either through physical damage by direct contact or release of toxic ions after ENPs dissolution process. Moreover, ENPs uptake, transformation and toxicity on physio-morphological, biochemical and molecular levels in primary producers of terrestrial environment (plants) were also reviewed. Additionally, the intrinsic detoxification mechanism in plants in response to ENPs accumulation was also examined. In the end different sustainable approaches such as biogenic synthesis, clay minerals role, biochar application, bioremediation, and legislative measures are proposed for effective handling and treatment of nano-wastes to get the maximum benefits of nanotechnology with minimum negative outcomes