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22841. 题目: Stable carbon isotope evidence for the origin of C28 steranes in lacustrine source rocks from the Qikou Sag, Bohai Bay Basin, Eastern China C27–C29 steranes are common constituents of crude oils and hydrocarbon source rocks, and are usually dominated by either C27 or C29 compounds. In the current study, however, steranes dominated by C28 components were detected in eight lacustrine source rock samples in the first member of the Shahejie Formation in the Qikou Sag, Bohai Bay Basin of Eastern China. Ratios of C28/(C27+C28 +C29) ααα20R steranes in four samples can exceed 50%. Furthermore, C27 triaromatic steroids, presumably originating from C28 steranes, were also observed at high levels relative to C26 and C28 homologues. Stable carbon isotope compositions of C28 ααα 20R sterane and C27 20R triaromatic steroid were found to be similar, with δ13C at -37‰ and -36‰ respectively, much lower than values for pristane (by ∼ 7‰) and total organic carbon (by ∼ 10‰). The abnormally low δ 13C values suggest that C28 ααα20R sterane is biosynthesized by algae blooming in the water column during phases of overturn and mixing, such as in autumn, during which recycled CO2 and nutrients welling up from hypolimnion to the epilimnion are assimilated, contributing to a high algal productivity and low δ13C in algal organic matter. | |||||
22842. 题目: Vegetation and species impacts on soil organic carbon sequestration following ecological restoration over the Loess Plateau, China Extensive soil organic carbon (SOC) accumulation has been reported following ecological restoration on the Loess Plateau of northwest China. While previous studies have found the restoration age to be a major factor controlling SOC change, potential effects of vegetation type and plant species have been largely neglected. Here, we compiled a database of 331 measurements of SOC changes following cropland restoration across the entire Loess Plateau. Results from stepwise multiple linear regressions indicated dominant contributions by restoration age, vegetation type or plant species, and/or their interactions in post-restoration SOC accumulation, accounting for 67–86% of the variation in SOC sequestration being explained by the model. Of the four restoration types examined, managed grassland was found to have the highest SOC sequestration rate (0.41 Mg C hm−2 yr−1), followed by plantation (0.27 Mg C hm−2 yr−1) and shrubland (0.25 Mg C hm−2 yr−1), with the lowest value found for naturally recovered grassland (0.13 Mg C hm−2 yr−1). The different SOC sequestration capacities for these vegetation types were further confirmed by an independent mechanistic modeling approach based on SOC turnover rate. Our results highlight the critical role of plant type in determining SOC sequestration following revegetation over cropland. Such management-relevant information should be considered in future restoration efforts. | |||||
22843. 题目: Predominance of hexamethylated 6-methyl branched glycerol dialkyl glycerol tetraethers in the Mariana Trench: source and environmental implication | |||||
22844. 题目: Increase of High Molecular Weight Organosulfate with Intensifying Urban Air Pollution in the Megacity Beijing Organosulfates (OSs), a key component of secondary organic aerosols (SOA), account for up to one third of organic matter in the atmosphere. However, high‐molecular‐weight (HMW, 500–800 Da) OSs in ambient aerosols are poorly characterized at a molecular level, due to experimental difficulties. With Fourier transform‐ion cyclotron resonance mass spectrometry (FT‐ICRMS), we are able to identify more than eight thousand OSs in wintertime aerosols in Beijing. We found that both the number and signal magnitudes of HMW OSs with low H/C and O/C ratios and degrees of unsaturation were greatly enhanced during hazy days, indicating that most HMW OSs were freshly formed during stagnant air‐pollution episodes. They are most likely to be the oxidation products of semi‐ to low‐volatility precursors (e.g., polycyclic aromatic hydrocarbons and fatty acids) and have showed a strong influence of anthropogenic emissions. The molecular corridor analysis suggests that the high abundance of HMW aromatic‐like and aliphatic OSs considerably decreases the volatility of organic aerosols in the urban atmosphere. | |||||
22845. 题目: Seasonal manganese transport in the hyporheic zone of a snowmelt-dominated river (East River, Colorado, USA) | |||||
22846. 题目: Albedo of Black Carbon‐contaminated Snow across Northwestern China and The Validation with Model Simulation Light‐absorbing particles (LAPs) in snow can significantly reduce the snow albedo. Quantification of the influence of black carbon (BC), one of the most important LAPs, on snow albedo is essential for understanding the budgets of solar radiation on snow‐covered areas. We measured BC concentration in snow at 28 sites and snow albedo at 18 sites in a vast region across northwestern China in January 2018. The BC concentration was in a wide range of 40–1850 ng g–1. The presence of the BC reduced the snow albedo by 0.01–0.20 at the visible wavelength band (400–750 nm). The reduction differed from sites to sites with large values close to industrial areas that are characterized by high pollutants emission. Albedos simulated with a Snow, Ice, and Aerosol Radiation (SNICAR) model based on the measured BC agreed well with the measured albedos, with the deviation within ±0.03 and the average underestimation of <0.002. It worth noting that the retrieved effective snow grain radius was the key factor in snow albedo calculation. The BC‐induced radiative forcing was estimated to be 0.2–6.9 W m–2, indicating strong acceleration of snowmelt due to BC in northwestern China. All obtained data are extremely valuable for climate model validation associated with the albedo of BC‐contaminated snow cover. | |||||
22847. 题目: Drought cycles over the last 8, 200 years recorded in Maar lake Twintaung, Myanmar The tropical Asian regions are particularly prone to catastrophic droughts due to high temperature and evaporation and their sensitivity to variable oceanic‐atmospheric circulation. The extent to which future global warming may intensify droughts in this populous region is a matter of utmost concern. Palaeoclimatic data can help inform scientists learn more about the temporal patterns and drivers of monsoon change over geological timescales. In this paper, we present a new 8200 year biomarker record preserved in the annually laminated sediments of Maar Lake Twintaung, Myanmar. The δ13C27‐35 sedimentary record is mainly derived from leaf wax lipids in the lake catchment, which is presently dominated by C3 vegetation in the modern lake catchment. The δ13C27‐35 is mainly regulated by plant physiological and biochemical responses to drought stress; and as such, can be used as a proxy of past changes in moisture. The δ13C27‐35 record reveals distinct decadal‐to‐centennial scale droughts superimposed on a trend of gradually decreasing summer monsoon intensity from the mid‐Holocene to late Holocene. Within the limits of the dating uncertainties, these decadal‐to‐centennial scale droughts are found to be well‐correlated with the southward shift of the ITCZ. It highlights the importance of the ITCZ shift (tropical monsoon trough) in regulating monsoon rainfall in the region. In addition, most of the droughts are likely to be linked with active volcanism and solar minima, and suggest a coupled process between external drivers and internal climate dynamics. | |||||
22848. 题目: Application of biogas slurry rather than biochar increases soil microbial functional gene signal intensity and diversity in a poplar plantation Microbes play critical roles in the cycling of nutrients in forest ecosystems. Many studies have shown that the application of organic fertilizer can alter bacterial diversity; however, the responses of soil microbial functional genes to organic fertilization (particularly biogas slurry fertilization, or in combination with biochar) have not been elucidated as yet. We examined the responses of the abundance, diversity, and composition of soil microbial functional genes under five-years of fertilization. This fertilization involved low and high application rates of biogas slurry, at 250 and 375 m3 ha−1 yr−1, respectively, or in combination with low and high application rates of biochar, at 80 and 120 t ha−1, respectively, in a coastal poplar plantation of Eastern China. Compared to the control, the normalized signal intensity of genes in the major functional categories increased significantly in response to the quantity of applied biogas slurry, but insignificantly in response to the additional application of biochar. Subsequent to the application of biogas slurry, the functional gene evenness and Shannon index increased significantly; however, the addition of biochar to the biogas slurry had insignificant effects on the α-diversity of functional genes. These functional gene compositions under five different treatments were well distinguished, primarily through the application of biogas slurry. Our results revealed that the abundance of a large number of key functional genes involved in C, N, and P cycling were effectively increased, and these changes were well correlated with most soil properties. This study reveals the molecular level mechanisms that promote plant growth following organic fertilizer application, through the enhancement of soil microbial functional gene diversity. | |||||
22849. 题目: Distribution characteristics and mechanism of microplastics mediated by soil physicochemical properties Interaction between microplastics and soil is essential for the environmental fate of plastic particles. In this study, polystyrene microplastic particles (PSMPs) with a size of 0.047 μm were selected as the representative of microplastics. Five soil samples from different provinces in China were selected (named Harbin S1, Huainan S2, Jiangxi S3, Shaanxi S4 and Hainan S5, respectively) and their interaction characteristics and mechanism with PSMPs were investigated, which provided new insights into the environmental behavior of microplastics. The experimental data showed that the pseudo-first-order model well fit for the sorption kinetics data, and the microplastic sorption ability of the soil accorded with the following sequence: S3 > S2 > S1 > S4 > S5. The sorption isotherm data of PSMPs on soils fit a linear model well (R2 = 0.998). The sorption of MPs on soils was affected by pH, and the sorption ability weakened as the pH increased. Soil physicochemical properties play important roles in sorption of PSMPs, especially the content of soil organic carbon. The sorption capacity was positively correlated with soil organic carbon (R2 = 0.999) and Fe2O3 content (R2 = 0.967), while the sorption of clay showed opposite trend (R2 = 0.952). The sorption mechanisms of PSMPs on soils included surface sorption, electrostatic and hydrophobic interactions. Results of this study could be useful to better study the role of soil in the fate and transportation of plastic particles. | |||||
22850. 题目: Bio-geochemical evolution and critical element mineralization in the Cretaceous-Cenozoic coals from the southern Far East Russia and northeastern China A total of 23 coal and two carbonaceous shale samples of the Early Cretaceous-Miocene, collected from different basins in the Primorye and Sakhalin regions of Russia, and the Hunchun basin of northeastern China, were used in this study for determination of major oxides (by AES and XRF), trace elements (by ICP-MS), sulfur, carbon, carbon isotopes, and major components of extractable organic matter (wet-chemical and gas-chromatographic analyses). Interpretation of the obtained data was intended to elucidate geodynamic and other geological processes controlling bio-geochemical compositions and critical element mineralization of the studied coals. The data suggest that inorganic matter in the studied coals was derived mainly from the Paleozoic granites and the Cenozoic felsic and intermediate tuffs. The Early Eocene and, in particular, Oligocene epochs represent the two major mineralization events in the regions, resulting in enrichment of Ge, W, Be, Mo, Sb, Sr, Ba, REY (rare earth elements and Y), Th, and U in the coals. The two events were related respectively to the Indo-Eurasian collision followed by plate reorganization in the Pacific and the opening of the Sea of Japan. The geodynamic changes were probably associated with mantle-derived volcanic activity and intensive degassing, which enhanced the capability of surficial and ground waters to leach and redistribute trace metals. Organic matter played a significant role in the system of mineralization, starting from weathering of source rocks and ending at the coal diagenetic stage. Organic acids significantly accelerated leaching and transportation of the metals, while they, together with sulfate-reducing bacteria, kerogen, alcohols + ketones, and n-alkanols in particular, played an important role in metal precipitation, mainly through reactions of cation exchange and adsorption. | |||||
22851. 题目: Exploring water-soluble organic aerosols structures in urban atmosphere using advanced solid-state 13C NMR spectroscopy Water-soluble organic matter (WSOM) in air particles has profound effects on climate and human health. At the heart of this environmental significance of WSOM lies a complex set of compounds, of which a major fraction still often remains undeciphered. Yet, not all environmental problems require delving into the molecular-level identification of WSOM constituents. Understanding the contribution of different functional groups to whole aerosol WSOM composition offers a highly important structural dataset that enables a better representation of WSOM in climate studies. For the first time, advanced solid-state 13C nuclear magnetic resonance (NMR) techniques, including nearly quantitative 13C multiple cross polarization/magic angle spinning (multiCP/MAS), multiCP/MAS with dipolar dephasing, multiCP/MAS with 13C chemical shift anisotropy filter, and two-dimensional 1H–13C heteronuclear correlation (2D HETCOR), are applied to acquire an accurate quantitative structural description of whole aerosol WSOM collected in an urban atmosphere. Two urban aerosol WSOM samples collected in two short periods of time, under different wintry weather conditions, were investigated. NMR data successfully pinpointed the variability of whole aerosol WSOM composition, allowing to suggest source-specific structural characteristics for each sample in two short periods of time. A new structural model of urban aerosol WSOM was build based on this compositional data, showing the presence of three independent classes of compounds that vary both in content and molecular diversity within short periods of time: heteroatom-rich aliphatic (either chain or branched), carbohydrate-like moieties, and highly substituted aromatic units. These findings establish advanced solid-state NMR as a promising tool for probing the chemical structures of inhomogeneous aerosol WSOM in rapidly changing atmospheric conditions, allowing to resolve discrepancies between modeled and measured aerosol WSOM. | |||||
22852. 题目: Interactions between nanoscale zero valent iron and extracellular polymeric substances of anaerobic sludge The effects on the activity of anaerobic digestion (AD) of interactions between extracellular polymeric substances (EPS), a protective barrier of microorganisms towards toxic compounds, and nanoscale zero valent iron (nZVI) remain incompletely understood. In this work, EPS induced a dosage-dependent dispersion of nZVI clusters due to their effective accumulation on the nZVI surface. The small size of nZVI clusters and the formation of stable Fe-EPS complex promoted the dissolution of nZVI with a final increase of 15–20% H2 yield. Further characterizations of EPS demonstrated the presence of some semiquinones, like riboflavin, which may work as a sink to accept electrons from nZVI. This likely explains the EPS dosage-related reduction of H2 release rate in the initial stage and the possible decrease in nZVI reducibility responsible for disrupting cell integrity. Interactions between nZVI and EPS could improve the electrochemical activity of EPS, favoring microbial extracellular electron transfer. Therefore, the presence of EPS at relatively higher concentrations may 1) reduce the inhibition of nZVI to AD process by avoiding the fast accumulation of H2 and restricting damage to cell integrity; 2) benefit the methanogenesis process by providing more exogenous H2 from complete nZVI dissolution with higher electrochemical activity of EPS. This study provides insight into the interactions between EPS and nanoparticles with strong reducibility in biological wastewater treatment systems. | |||||
22853. 题目: Measurements of light-absorbing impurities in snow over four glaciers on the Tibetan Plateau Black carbon (BC), dust, and organic carbon (OC) aerosols, when deposited onto the surface of glaciers, can absorb light and decrease the snow albedo. These impurities in snow are referred to as ILAIs (i.e., insoluble light absorbing impurities). Atmospheric chemical models have been extensively used to simulate the transport and deposition of atmospheric aerosols in glacierized areas. However, systematic investigations of ILAIs in snowpack of glaciers on the Tibetan Plateau (TP) are rare. In this study, observations of ILAIs in snow and simulations of ILAIs of atmospheric aerosol at surface over four glaciers on the TP have been analyzed. Strong correlation between BC and dust was found in surface aged-snow, and their correlation significantly varied with snowpit depth. BC and OC concentrations in snowpit tended to decrease with depth. Significant differences of ILAI concentrations among depth intervals reflect their diverse hydrophilicities, physiochemical properties and post-depositional processes in snowpit, offering important observational constraints on the related processes. Monthly variation of atmospheric ILAIs at surface over glaciers is characterized by distinct spatial heterogeneity. The statistical results show higher ILAI concentrations in the summer of 2015 than 2014, which is in qualitative agreement with CALIPSO observations, likely reflecting the effects of inter-annual variation of summer monsoon on snow ILAI loadings. Optical attenuation (ATN) of BC is gradually decreased with depth of snowpit, whereas the trend of mass absorption cross-section (MAC) of BC throughout the profile of snowpit is opposite to that of ATN. The scanning electron microscopy (SEM) imaging demonstrates that calcium and silicon rich particles dominate over biological, quartz and flying ash particles in the cryoconite, providing additional constraints on the sources of dust-in-snow and can facilitate better understanding of the physicochemical properties and climatic effects of particles in the glacial cryoconite. | |||||
22854. 题目: Cycling Phosphorus on the Archean Earth: Part II. Phosphorus Limitation on Primary Production in Archean Ecosystems Several lines of evidence point to low rates of net primary production (NPP) in Archean oceans. However, whether Archean NPP was limited by electron donors or nutrients, particularly phosphorus (P), and how these factors might have changed over a billion years of recorded Archean history, remains contentious. One major challenge is to understand quantitatively the biogeochemical cycling of P on the early Earth. In Part I of this series (Hao et al., 2020), we estimated the weathering flux of P to the oceans as a function of temporally increasing continental emergence and elevation through Archean time. In Part II, we conduct thermodynamic and kinetic simulations to understand key processes of P cycling within the Archean ocean, including seafloor weathering, recycling of organic P, the solubility and precipitation of secondary phosphate minerals, and the burial diagenesis of P precipitates. Our calculations suggest low solubilities of apatite minerals in Archean seawater, primarily due to nearly neutral pH and high levels of Ca. This low solubility, in turn, implies a negligible contribution of apatite dissolution to P bioavailability in Archean seawater. We also simulate the solubility limits of common secondary P-bearing minerals, showing that vivianite would have been the least soluble P mineral in ferruginous Archean seawater (0.1 to 0.3 µM), even at moderate supersaturation states (Ω = 100 or 1000). If vivianite precipitation was kinetically favorable by microbial activities and mineral adsorption, the sinking flux of P as vivianite in Archean seawater could have reached the modern sinking flux, implying that vivianite precipitation was a potentially major sink for P in Archean oceans. During burial diagenesis, however, vivianite in porewater would have become less stable than Ca-phosphates of lower solubility. At elevated temperatures (>100 °C) associated with burial diagenesis and low-grade metamorphism, vivianite is predicted to react irreversibly with calcite to form apatite. Optimistic assumptions about the recycling efficiency of P on the Archean Earth lead us to estimate that by the end of the eon the total flux of P (continental weathering + recycling) could have supported NPP at levels up to 7 % of the modern. The total flux of P would have been much lower on the early and middle Archean Earth, whereas fluxes of electron donors could have been higher, suggesting very low productivity and P-limitation of marine ecosystems during much of the eon. Comparing our estimates of NPP as limited by P supply with the estimate by Ward et al. (2019), in which NPP was limited by electron donors and metabolic efficiency, there could have been a transition between P-limited productivity in the early to middle Archean to electron donor-limitation closer to the eon's end (assuming no oxygenic photosynthesis). Once oxygenic photosynthesis reached ecological significance, probably near the end of the Archean, our estimated flux of P would allow rapid oxidation of atmosphere. | |||||
22855. 题目: Sediment quality of the Bohai Sea and the northern Yellow Sea indicated by the results of acid-volatile sulfide and simultaneously extracted metals determinations The surface sediments from the Bohai Sea (BS) and the northern Yellow Sea (NYS) were analyzed for acid-volatile sulfide (AVS) and simultaneously extracted metals (SEM) to assess the sediment quality. The results indicated that >60% of the samples were found to have possible adverse effects on aquatic life in the BS based on the difference between the concentrations of AVS ([AVS]) and SEM ([SEM]), and the corresponding percentage in the NYS was <25%. Nevertheless, there was no indication of adverse effects for all the BS and the NYS samples when the total organic carbon (TOC) concentration was introduced in the sediment quality evaluation with [AVS] and [SEM]. The grain size composition, TOC, water content and pH all had significant influence on the distribution of [SEM] and the [SEM]/[AVS] ratios; while, in contrast, the distribution of [AVS] could be mainly determined by the redox condition of sediment. | |||||
22856. 题目: Tuning surface functionality of standard biochars and the resulting uplift capacity of loading/energy storage for organic phase change materials Biochars have been suggested as cheap, eco-friendly, and commercially available media for adsorbing various organic and inorganic target compounds. However, there is a dearth of systematic examinations on the design of shape and thermally stable organic phase-change materials (PCMs). In this investigation, composite PCMs based on standard biochars (derived from miscanthus straw, oilseed rape, and sewage sludge feedstock via pyrolysis (at 700 °C)) and organic PCMs (1-dodecanol and n-dodecane) were developed. The as-prepared composite PCMs revealed enhanced thermal stabilities, chemical compatibilities, and moderate heat transfer performances. Among these biochar-derived composites, one from oilseed rape exhibited high heating enthalpy of 73.7 and 90.5 kJ/kg for 1-dodecanol and n-dodecane, respectively. The impregnation volume of dodecane-based composite reached 71.6%, which can be ascribed to the favorable structural (e.g., high specific surface area and high mesopore proportions) and morphological characteristics of the supporting materials. The synthesis of 1-dodecanol-based composite appeared to be influenced by specific surface areas of the biochars and intermolecular interactions owing to the highly sensitive hydroxyl group of the organic PCM. In general, this study is expected to serve as a foundation for the synthesis of green composite PCMs in the thermal energy storage sector. | |||||
22857. 题目: A comparative study of waste activated sludge disintegration by electrochemical pretreatment process combined with hydroxyl and sulfate radical based oxidants In this study, electrochemical treatment (EC) combined with hydrogen peroxide (HP), calcium hypochlorite (CHC), peroxymonosulfate (PMS) and peroxydisulfate (PDS) was investigated as a pretreatment process for improving waste activated sludge (WAS) disintegration in terms of soluble chemical oxygen demand (sCOD). A pair of Fe-Fe electrodes were used in the study, and the main operation parameters were determined as oxidant dosage, initial pH, applied current, electrolysis time and concentration of electrolyte solution (Na2SO4). The maximum disintegration degrees in terms of the COD (DDCOD) values were found 11.80 %, 11.11 %, 9.61 % and 10.65 % for EC combined with HP, CHC, PMS and PDS treatments at the optimized conditions, respectively. DD values were also calculated for total organic carbon (TOC) and total nitrogen (TN) concentrations after the pretreatment at the optimum conditions, and lower DDTOC values and almost equal DDTN values to DDCOD were obtained. Capillary suction time analyses were performed to determine WAS dewaterability, and reductions of 27.34 %, 29.25 % and 36.13 % CST were found for EC combined with the CHC, PMS and PDS treatments, respectively. EC-HP combination did not enhance WAS filterability, as the CST value increased from 13.1 s of raw sludge to 18.1 s of HP-treated sludge. Extracellular polymeric substance (EPS) types and concentrations were also investigated at the optimized conditions, and the concentrations of polysaccharide and protein increased in soluble EPS (S-EPS). On the other hand, both protein and polysaccharide components decreased in loosely-bound EPS (LB-EPS) and tightly-bound EPS (TB-EPS) in almost all treatments. EC-HP pretreatment was found to be the best combination in order to enhance disintegration of WAS, whereas EC-PDS combination was the best for WAS dewaterability, among all treatment application. | |||||
22858. 题目: Non-destructive spatial analysis of phosphatase activity and total protein distribution in the rhizosphere using a root blotting method Phosphorus (P) is an essential macronutrient for plant growth, but bioavailable P in soils is often limited due to immobilization resulting from pH and geochemical interactions. Understanding the dynamics of P in soils and elucidating the mechanisms by which plants access P from their environment are critical to evaluating productivity, particularly in nutrient poor environments. Phosphorus from organic matter can act as a major source of P for organisms in soil systems. Phosphatases, enzymes that liberate inorganic P from organic sources, are produced by both plants and microbes and are considered one of the most active classes of enzymes in soil. We developed a root blotting method to spatially image phosphatase activity in the rhizosphere. Proteins from the rhizosphere are transferred to a nitrocellulose membrane while retaining their enzymatic activity and two-dimensional spatial distribution. Subsequent application of a fluorogenic phosphatase indicator, DDAO phosphate, enables visualization of the distribution of phosphatase activity in the sample. The proteins can then be fixed to the membrane and treated with SYPRO® Ruby Protein Blot Stain, a fluorescent total protein stain, allowing for visualization of total protein distribution. Taken together, the images of phosphatase activity and total protein localization can be mapped back to the root architecture and provide insight into factors affecting the spatial distribution of enzymatic activity and protein accumulation in the rhizosphere. Notably, this method can be applied to plants growing in rhizoboxes containing soil or soilless growth mixtures (e.g., sand or various potting mixes) and, because of the non-destructive nature of this approach, be performed over time to track changes. We anticipate that this fluorescent indicator imaging technique on root blots can be used in diverse plant-microbe-soil systems to better understand the role of phosphatases in P acquisition and soil P cycling. | |||||
22859. 题目: Response of soil microbial communities to additions of straw biochar, iron oxide, and iron oxide–modified straw biochar in an arsenic-contaminated soil | |||||
22860. 题目: Carboxyl and hydroxyl groups enhance ammonium adsorption capacity of iron (III) chloride and hydrochloric acid modified biochars The effectiveness of the modification of wheat straw biochar using FeCl3 and HCl, alone or combined, on ammonium adsorption was evaluated using kinetic and isotherm models. The adsorption mechanisms were studied by comparative analysis of the surface properties of the biochars before and after ammonium adsorption. The results indicate that the modification methods enhanced the ammonium adsorption capacity by at least 14%, due to the increased -OH and O-C=O functional groups and specific surface area, and increased Fe3+/Fe2+ redox coupling serving as an electron shuttle. It can be concluded that chemical modification of wheat straw biochars using FeCl3 and HCl increased the effectiveness of biochars for the treatment of ammonium-contaminated wastewater. | |||||
