Carbon Fractions Research Articles

Insights into the Properties of Type Ibn/Icn Supernovae and Their Progenitor Channels through X-Ray Emission

Abstract Type Ibn/Icn supernovae (SNe Ibn/Icn), which are characterized by narrow helium or carbon lines that originated in hydrogen-poor dense circumstellar medium (CSM), provide new insights into the final evolution of massive stars. While SNe Ibn/Icn are expected to emit strong X-rays through the strong supernova (SN)-CSM interaction, the X-ray emission modeling effort has been limited so far. In the present study, we provide broad-band X-ray light curve (LC) predictions for SNe Ibn/Icn. We find that the soft X-ray LC provides information about the CSM compositions, while the hard X-ray LC is a robust measure of the CSM density, the explosion energy, and the ejecta mass. In addition, considering the evolution of the ionization state in the unshocked CSM, a bright soft X-ray is expected in the first few days since the explosion, which encourages rapid X-ray follow-up observations as a tool to study the nature of SNe Ibn/Icn. Applying our model to the soft X-ray LCs of SNe Ibn 2006jc and 2022ablq, we derive that the CSM potentially contains a larger fraction of carbon and oxygen for SN 2006jc than 2022ablq, highlighting the power of the soft X-ray modeling to address the nature of the CSM. We also discuss detectability and observational strategy, with which the currently operating telescopes such as NuSTAR and Swift can offer an irreplaceable opportunity to explore the nature of these enigmatic rapid transients and their still-unclarified progenitor channel(s).

Historical Variation in Carbon Fractions in Permafrost Peatland and Its Effects on Peatland Carbon Pool

ABSTRACTPermafrost peatlands store high amount of soil carbon. These developed on permafrost layers, which are being endangered increasingly by climate change and wildfires. However, limited data exist on the variation in carbon fractions and their effects on the stability of permafrost peatland carbon pools, despite that carbon fractions are widely used in other ecosystems. Here, we considered that peat soils consist of undecomposed plant litter and separated these into five carbon fractions: macro plant residue carbon (MPRC), coarse particulate organic carbon (cPOC), free particulate organic carbon (fPOC), occluded particulate organic carbon (oPOC), and mineral‐associated organic carbon (MAOC). We analyzed the historical variation in these fractions over the past 700 years and their effects on the carbon pool in the Hongtu peatland (HT, northern Great Khingan Mountains, China). Our results showed that MPRC comprised 66.7% ± 7.6% of the carbon pool, whereas oPOC and MAOC accounted for less than 1%. Notably, fPOC, which represented 15.6% ± 6.5% of the total carbon, had a high aromatic content. It may serve as an important stable carbon fraction for the peatland carbon pool. Over the past 700 years, the decrease in proportion of MPRC and increase in proportions of cPOC and fPOC have resulted in significant increases in both carbon content and aromaticity. Warm/dry conditions and high‐intensity fires reduced the accumulation rates (ARs) of MPRC while increasing those of fPOC and cPOC. The high organic carbon content in the HT peatland limited the availability of mineral elements and resulted in MAOC ARs of approximately 0.01 g m−2 yr−1. This was strongly influenced by the regional dust deposition. Cold climates and intense fires caused an increase in dust deposition, which also increased the MAOC ARs.

Carbon and Mercury Stable Isotope Fractionation during Aqueous Photodemethylation of CH3Hg

Carbon and Mercury Stable Isotope Fractionation during Aqueous Photodemethylation of CH₃Hg

Soil organic carbon and related properties under conservation agriculture and contrasting conventional fields in Northern Malawi

Conservation agriculture (CA) is widely promoted as an agroecology-based approach for soil conservation. Several studies have focused on effects of CA on crop yields and soil moisture dynamics in sub-Saharan Africa, with limited focus on effects of CA on soil organic carbon (SOC) and associated fractions. We collected representative soil samples from 30 paired farms under CA and conventional tillage in Mzimba district, north of Malawi to determine effects of tillage and soil depth on soil physico-chemical properties, total SOC, and organic carbon fractions. Undisturbed soil cores were collected for bulk density measurements. Different SOC pools were determined using the soil fractionation method, while soil physico-chemical analyses were conducted using standard laboratory methods on disturbed soil samples. Soil organic carbon content ranged from 0.4-1.8% in CA plots. This was significantly larger than SOC contents of 0.4-1.5% measured under conventional tilled plots. Tillage type and soil depth had significant interaction effects on SOC. For example, larger contents of SOC were measured at depths of 0-10 cm compared to 10-30 cm under CA plots. Soil depth had significant effects on most soil properties compared to tillage. Examples include Heavy Particulate Organic Matter-Carbon (POM-C) fraction, Mineral Associated Organic Matter-Carbon (MAOM-C), nitrogen in MAOM fraction and nitrogen in the Light POM fractions. These were larger in the 0-10 cm soil depth than in the 10-30 cm soil depth. In contrast, tillage type only had significant effects on the Heavy POM-C and MAOM-C fractions, which were larger under CA than conventional tilled plots. Conservation agriculture showed capacity to improve total SOC and its associated fractions, a finding relevant towards understanding effects of land management on carbon storage. However, challenges of competing residue use as feed, mulch, and fuel continue to impede mulching under CA systems. Longer term studies and use of alternative mulching options could be employed to recognise noticeable changes in other SOC beneficial pools in fields under CA.

Wild boar grubbing affects soil carbon quantity and fractions under native, reforested and planted vegetation

Wild boar grubbing affects soil carbon quantity and fractions under native, reforested and planted vegetation

Divergent responses of soil aggregate-associated organic carbon fractions and carbon flow pathways to land-use changes in karst ecosystems: Insights from δ13C signature

Divergent responses of soil aggregate-associated organic carbon fractions and carbon flow pathways to land-use changes in karst ecosystems: Insights from δ13C signature

Identifying bacterial fixation pathway of mediating soil carbon stock changes along tropical forest restoration

The mechanism mediating carbon accumulation changes along ropical forest restoration remains unclear. Here, we identified how functional bacteria, litter input, and abiotic variables control soil organic carbon stock changes along an age-chronosequence of tropical forest restoration. Over 51-yr recovery, significant increases in total organic carbon stocks (∼1.7 fold) were strongly associated with increases in copy number of carbon fixation bacterial genes (cbbL) (∼2.6 fold). The direct pathways of cbbL abundance, microbial and mineral-associated organic carbon explained 76 % of carbon stock variation. In contrast, litter carbon, soil water, and bulk density indirectly regulated carbon stocks through affecting cbbL abundance (68 %) and microbial carbon level (29 %). Furthermore, cbbL abundance had a higher contribution (71 %) to carbon fraction transformation than microbial carbon level (19 %). We suggest that tropical forest restoration controls carbon stocks primarily via direct bacterial fixation pathway mediated by litter carbon and physical soil variables. Our results are helpful to further understand the mechanism of tropical forest restoration regulating carbon transformation and accumulation.

Effects of long-term conservation tillage on soil aggregate carbon fractions and microbial characteristics under rice-oilseed rape rotation systems

Effects of long-term conservation tillage on soil aggregate carbon fractions and microbial characteristics under rice-oilseed rape rotation systems

Efficacy and safety of combined fractional carbon dioxide laser and topical timolol maleate 0.5% solution versus topical timolol maleate 0.5% solution alone in inflammatory facial acne; a randomized split face controlled study.

In this study, we aimed to investigate the efficacy and safety of combined fractional carbon dioxide laser and topical timolol maleate 0.5% solution versus topical timolol maleate 0.5% solution alone in inflammatory acne. Thirty adult patients with inflammatory facial acne were randomized in this study. The patients received 3 biweekly sessions of fractional CO2 laser on one side of the face followed by topical timolol maleate ophthalmic solution 0.5% once daily for 7 days on both sides. Outcome was evaluated 2 weeks after the first session, 2 weeks after the last session, and 1 month after the last session by lesion count, erythema, hyperpigmentation, qualitative global scarring grading, and patients' satisfaction. Side effects were also evaluated. Trial registration (IRB No. 417, 30/10/2023). At 2 weeks after the first session, there were insignificant differences between both sides regarding lesion count, erythema, hyperpigmentation, and qualitative global scarring grading (p value = 0.8, 0.05, 0.7, 0.1 respectively). At 2 weeks after the last session, the erythema on the combined side was reduced by a mean of 0.2 ± 0.4 SD compared to timolol only side with significant difference between both sides (p value = 0.03), while there were insignificant differences between both sides regarding lesion count, hyperpigmentation, qualitative global scarring grading, and patients' satisfaction (p value = 0.1, 0.5, 0.8, 0.3 respectively). Recurrence was detected at one month after the last session. No side effects were reported. Combined fractional CO2 laser and topical timolol maleate 0.5% solution were significantly more effective than topical timolol maleate 0.5% solution alone in reduction of erythema of inflammatory facial acne in adolescent men with Fitzpatrick's skin type III-IV at 2 weeks after 3 biweekly sessions with insignificant differences between both sides regarding lesion count, hyperpigmentation, qualitative global scarring grading, and patients' satisfaction. Further and larger studies are still needed.

Long-Term Organic Substitution Regimes Affect Open-Field Vegetable Yields and Soil Organic Carbon Stability by Regulating Soil Labile Organic Carbon Fractions’ Changes

Soil labile organic carbon (C) fractions play a key role in agricultural soil fertility. However, the effects of long-term organic substitution regimes on soil organic carbon (SOC), its labile fractions, stability, and vegetable yields as well as the relationships among these factors in the open-field are less well-studied. Hence, the objective of this study was to analyze the effects of long-term organic substitution regimes on SOC sequestration, labile C fractions [particulate organic C (POC), microbial biomass carbon (MBC), dissolved organic C (DOC), and readily oxidizable C (ROC)], SOC stability, the C pool management index (CMI), and vegetable yields in a long-term (13 years) open-field experiment. Five treatments were examined: 100% chemical nitrogen fertilizer (CN), substituting 25% of the chemical N with manure (MN) or straw (SN), and substituting 50% of the chemical N with manure (2MN) or manure plus straw (MSN). Compared to the CN, organic substitution treatments increased the average yields of vegetable, the SOC, the labile C fractions’ contents, and the C pool management index (CMI) to varying degrees, but only MSN reached significant levels for these factors. However, the MSN treatment had a significantly lower C stability index (SI) than the CN. 13C-NMR analyses also confirmed that organic substitution treatments increased the proportion of O-alkyl C and the OA/A, but reduced SOC stability. Pearson correlation analysis and the partial least squares path model indicated that labile C fractions were the mainly direct contributors to yield and SOC stability. Overall, substituting 50% of the chemical N with manure plus straw is a relatively ideal fertilization practice to improve vegetable yields and enhance C activity in an open field.

Long-term Organic and Inorganic Fertilization Affect Soil pH, Humus Carbon Fractions, and Crop Yield in Three Soil Types

Context: Soil acidification and humus carbon depletion pose significant challenges to agricultural sustainability. Organic and inorganic fertilization influence soil pH, humus carbon, and crop yield, yet the effects in different soil types remain inadequately understood. Objective: This study aimed to (i) measure soil pH changes under different long-term organic and inorganic fertilization in granite, Quaternary red, and purple sandy shale soils, (ii) quantify humus carbon content and humification degree, and (iii) explore the implications for crop yield in these soils. Methods: A field experiment was conducted in 2023 based on a long-term study established in 1982 at the National Observation and Research Station of Farmland Ecosystem in Qiyang, south China. Six treatments were applied: CK-T (control with straw take away), CK-R (control with straw return), NPK-T (NPK with straw take away), NPK-R (NPK with straw return), OM-T (straw take away), and OM-R (straw return). Results: Soil pH was highest under the OM-R treatment, while NPK-T and NPK-R significantly reduced pH in Quaternary red and granite soils compared to purple sandy shale soil. NPK-R and OM-R treatments significantly increased humus carbon fractions, humic acid carbon (HA-C), fulvic acid carbon (FA-C), and humin carbon (HU-C) in all three soils. The NPK-R treatment increased the soil organic carbon (SOC) and soil microbial biomass carbon (SMBC) in granite soil than in Quaternary red and purple sandy shale soils. The average humic acid to fulvic acid ratio (HA:FA) across all treatments was 1.46, with the purple sandy shale soil exhibiting the highest humification degree (HA:FA 1.51), surpassing Quaternary red (HA:FA 1.49) and granite soils (HA:FA 1.38). NPK-R treatment produced the highest sweet potato (Ipomoea batatas 'Beauregard') yields in granite (25,000 kg ha⁻¹) and Quaternary red soils (24,012 kg ha⁻¹) and the highest broad bean (Vicia faba 'Aquadulce Claudia') yield (632.8 kg ha⁻¹) in purple sandy shale soil. Both crop yields were strongly correlated with soil pH, humus carbon fractions, SOC, TN, AP, AK, BD, and SWC. Conclusion: Straw return stabilizes soil pH, whereas NPK fertilizer reduces soil pH. Straw application with NPK fertilizer increases humus carbon content, nutrient concentrations, and crop yield. These findings provide valuable insights into the synergistic effects of straw and mineral fertilizers on soil properties, contributing to crop yield improvement in different soil types.

Impacts of the Ecosystem Transformation in Red Jujube Commercial Forests on the Soil Organic Carbon Sources and Stability in the Lvliang Mountains

ABSTRACTSoil organic carbon (SOC) stabilization is vital for the mitigation of global climate change and retention of soil carbon stocks. The Loess Plateau is a crucial ecological zone in China and even worldwide for major ecosystem protection. However, in the Loess Plateau, there are knowledge gaps about the response of SOC sources and stabilization to different ecological transitions of jujube economic forests. Therefore, our study used clean‐cultivated jujube orchards as a control (CK) and selected five main ecosystem transformation models of abandoned jujube orchards on Lvliang Mountain: abandoned farmland (AF), replanted with Astragalus‐Bupleurum (AB), replanted with alfalfa (AL), replanted with Chinese pine (CP), and replanted with Chinese arborvitae (PO). The soil properties, sources and physical fractions of organic carbon and their correlations in the 0‐ to 20‐cm soil layer at each sample site were analyzed. The results show that the ecosystem transformation significantly increased the SOC by affecting plant‐ and microbe‐derived carbon and altering its components. Different treatments have varying impacts on the SOC content. The lignin phenol (VSC) content in the soils in the five ecosystem transformation models was greater than that in the CK and had the following ranking: CP > AL > PO > AF > AB (p < 0.05). The ecosystem transformation also significantly increased the soil total amino sugar (TAS) content, microbial residue carbon (MRC), and its contribution to organic carbon. Additionally, it promoted the accumulation of particulate organic carbon (POC) and mineral‐associated organic carbon (MAOC) and positively impacted the carbon stability. Among the five ecosystem transformation models, CP had the greatest impact on lignin phenols, amino sugars, SOC content, and stability, whereas AF and AB contributed the least to SOC. The results of this study provide a scientific basis to assess and select optimal transformation modes for the ecosystem transformation of commercial jujube forests.

Unraveling the Impact of Diverse Vegetative Covers on Soil Carbon Fractions

Evaluating SOC lability is crucial for sustainable agriculture policies and environmental quality. This study assessed the impact of well-stocked forest cover on SOC pools and lability compared to shrubby soil. Geo-referenced soils under Red pine (Pinus brutia), Black pine (Pinus nigra), Cedar (Cedrus libani), Fir (Abies cilicia), Juniper (Juniperus excelsa), Oak (Quercus L.), Carob (Ceratonia siliqua), and degraded shrubs were collected from a depth of 0 to 30 cm in the Seyhan River Basin, Mediterranean Turkey. The analysis of soil organic carbon (SOC), soil AC (active carbon), and PC (passive carbon) were analyzed to understand soil carbon management across diverse vegetation types. Juniper forests have the highest SOC (27.98 g/kg) and PC (27.35 g/kg), followed by Cedar (SOC: 27.64 g/kg, PC: 27.05 g/kg) and Fir (SOC: 26.44 g/kg, PC: 25.85 g/kg). Shrubby areas have the lowest SOC (4.06 g/kg) and PC (3.61 g/kg). The Oak soil had the highest CLI (1.16), suggesting a relatively higher proportion of labile carbon than other forests. CPI indicates forests have a greater carbon storage capacity (1.09) compared to shrublands (0.18), with forests also having a higher CMI (0.83). The findings emphasize the critical role of forests, especially Juniper forests, in carbon sequestration and climate change mitigation within the Seyhan River Basin in Turkey.

Treatment of Surgical Scars with Fractional Carbon Dioxide (CO2) Laser: A Randomized Controlled Trial.

Object: The aim of this study was to compare the long-term effects of fractional carbon dioxide (CO2) laser treatment with traditional therapy on surgical scars by analyzing and comparing observational indicators. Approach: A randomized controlled trial was conducted on 116 patients who received scar treatment in our hospital, of which 58 patients received fractional CO2 laser treatment, and 58 patients received injection treatment. The outcome measures comprised the Vancouver Scar Scale (VSS) and the Patient and Observer Scar Assessment Scale (POSAS). The observation intervals occur at specific times. Evaluated at 6 months of follow-up, the outcome was blinded, on-site evaluation using the dermatological appearance scale (DAS) and visual analog scale (VAS). Results: Patients in the fractional carbon-dioxide laser (CO2FL) group rated better than those in the injection group in the POSAS, VSS, DAS, and VAS scores (p < 0.05). The therapeutic efficacy and patients' satisfaction of the research group were superior to those in the control group. Innovation: Scars following surgical procedures can be treated in a variety of methods, but there is no consensus on the best method. CO2FL has exhibited safety and is more effective than traditional injection treatments for surgical scars. It is a worthwhile approach to consider in clinical treatment. Conclusions: This study demonstrates that CO2FL achieves more significant long-term results in surgical scars, including improved scar appearance, safety, and patient satisfaction.

A Novel Capacitor Deionization Performance Study Based on Carbon Nanorods/MnO2 Composite Material

The Earth abounds in water resources; however, only 0.4% of the freshwater resources are suitable for drinking. The scarcity of freshwater resources has a severe impact on the sustainable development of human society. Desalination is regarded as one of the most effective solutions. In this study, a research approach integrating materials and devices was utilized to synthesize manganese oxide-coated carbon nanospheres (CS@MnO2). Experimental results demonstrated that the system, by combining the distinctive performance merits of the CS@MnO2 material and the balanced desalination features, exhibited outstanding desalination performance. In the EDS elemental mapping analysis, the relatively feeble signal of carbon was ascribed to the encapsulation of MnO2 on the outer surface of CS. Through computational TGA analysis, the mass fraction of carbon in CS@MnO2-2 was determined to be approximately 51.2%. The excellent hydrophilicity of the material facilitated the permeation of the salt solution throughout the electrode, thereby enhancing the capacitance. CS@MnO2-2 manifested a high salt adsorption capacity of 27.42 mg g⁻¹ and the fastest electrosorption rate of 7.81 mg g⁻¹ min⁻¹. During 50 adsorption desorption cycles, the adsorption capacity showed good results. The adsorption kinetics and adsorption isotherm fitting indicated that the desalination process involved electrostatic and multilayer adsorption. This study holds great significance for reducing the cost of desalinated water and guaranteeing a sustainable supply of freshwater resources.

Tea cultivation: facilitating soil organic carbon accumulation and altering soil bacterial community-Leishan County, Guizhou Province, Southwest China.

Camellia sinensis is an important cash crop in southwestern China, with soil organic carbon playing a vital role in soil fertility, and microorganisms contributing significantly to nutrient cycling, thus both of them influencing tea tree growth and development. However, existing studies primarily focus on soil organic carbon, neglecting carbon fractions, and the relationship between soil organic carbon fractions and microbial communities is unclear. Consequently, this study aims to clarify the impact of different tea planting durations on soil organic carbon fractions and microbial communities and identify the main factors influencing microbial communities. It provides a theoretical basis for soil quality evaluation in the study area and scientific guidance for tea plantation management, thus fostering the region's economic sustainability. This study selected tea plantations with different tea planting durations of 3-5 years (Y5), 12-16 years (Y15), 18-22 years (Y20), 40-42 years (Y40), and 48-50 years (Y50), as research subjects and adjacent uncultivated forest without a history of tea planting (CK) served as controls. Soil organic carbon (SOC), particulate organic carbon (POC), easily oxidizable organic carbon (EOC), dissolved organic carbon (DOC), microbial biomass carbon (MBC), and bacterial diversity were measured in the 0-20 cm and 20-40 cm soil layers, respectively. Compared to the adjacent uncultivated forest (CK), the soil organic carbon (SOC), easily oxidizable carbon (EOC), particulate organic carbon (POC), and dissolved organic carbon (DOC) contents in a 40-year tea plantation significantly increased. Nonetheless, the microbial biomass carbon (MBC) content notably decreased. POC/SOC ratios rose with prolonged planting, signifying enhanced conversion of organic carbon into particulate forms. Bacterial community diversity peaked at 15 years and declined by 40 years post-planting and after tea planting dominated by Acidobacteriota, Chloroflexi, Proteobacteria, and Actinobacteriota in the tea garden. FAPROTAX analysis highlighted aerobic and anaerobic chemoheterotrophy, cellulolysis, and nitrogen fixation as key bacterial functions. POC and MBC significantly influenced bacterial community structure. In conclusion, tea plantation soil exhibited the highest organic carbon content at 40 years of tea planting, indicating strong carbon accumulation capacity. However, soil acidification in the tea plantation may affect changes in organic carbon and bacterial community. Therefore, in the tea planting process, it is necessary to improve the management system of tea plantations to ensure the maintenance of a good ecological environment in the tea plantation soil, thus achieving sustainable development of the tea industry in the region.

Effects of Low-Severity Fire on the Composition and Stability of Soil Organic Carbon in Permafrost Peatlands (Northeast China).

Climate change and human activity are increasing the frequency of wildfires in peatlands and threatening permafrost peatland carbon pools. In Northeast China, low-severity prescribed fires are conducted annually on permafrost peatlands to reduce the risk of wildfires. These fires typically do not burn surface peat but lead to the loss of surface vegetation and introduction of pyrogenic carbon. However, the long-term effects of repeated low-severity fires on soil carbon stability in these ecosystems remain unclear. Thus, we conducted low-severity prescribed fire experiments over 3 years in the permafrost peatlands of the Great Khingan Mountains. Our findings showed a gradual decline in the total carbon content, primarily due to the reduction in free particulate organic matter (fPOM). Initially, fPOM was higher in the burned sites but decreased with repeated burning. Chemical analyses revealed a 32% increase in the aromaticity of the fPOM at the burned sites, which diminished the thermal stability of the soil. Furthermore, both prescribed fires and the addition of pyrogenic carbon reduced biological stability while increasing enzyme activity and CO2 production, which was attributed to the introduction of post-fire pyrogenic carbon. These results suggest that low-severity fires compromise the stability of permafrost peatlands, particularly because the pyrogenic carbon input alters the chemical composition of the soil carbon fraction.

The efficacy of fractional CO2 laser with or without triamcinolone acetonide or 5-fluorouracil in the treatment of early postburn hypertrophic scars

Hypertrophic scars (HTSs) are the result of an abnormal healing process resulting from burns and other severe traumas. The symptoms of that condition include skin irritation, discomfort, and itching. This study aimed to assess the efficacy of fractional carbon dioxide (CO2) laser therapy alone or with triamcinolone or 5-fluorouracil (FU) in the treatment of early post-burn hypertrophic scars (HTSs) that develop during the first 6 months after the injury. A prospective, randomized, single-blind comparative study was conducted on 30 patients aged 16–65 with hypertrophic scars (HTS) resulting from burns. Patients had no prior treatment for their scars. We randomly assigned participants to one of three groups: Group A received fractional CO2 laser therapy alone, Group B received fractional CO2 laser therapy with topical 5-fluorouracil, and Group C received fractional CO2 laser therapy with topical triamcinolone acetonide. All treatment groups showed significant improvements (p < 0.05) in overall scar severity and height. Patients in Group C (fractional CO2 laser + triamcinolone) demonstrated significant improvements in scar pliability, height, and pigmentation (p < 0.05). In contrast, patients in Group B (fractional CO2 laser + 5-FU) showed significant reductions in scar vascularity, pliability, and height following treatment (p < 0.05). While all groups reported minor changes in pain and itching, there were no significant differences in these symptoms between Group B and Group C. HTSs of this trial revealed reductions in overall scar surface area and thickness and improvement of pliability and pigmentation; however, there was not statistically significant difference between the effect of 5-fluorouracil and triamcinolone acetonide (TAC), suggesting that neither drug offers better efficacy over the other. Level I, singleblinded randomized control study.

Effect of ablative fractional carbon dioxide laser combined with 1064 nm-Nd: YAG laser in the treatment of postburn hypertrophic scar

Effect of ablative fractional carbon dioxide laser combined with 1064 nm-Nd: YAG laser in the treatment of postburn hypertrophic scar

Functionalization of sawdust biochar using Mg-Fe-LDH and sodium dodecyl sulfonate enhanced its stability and immobilization capacity for Cd and Pb in contaminated water and soil

The increased contamination of potentially toxic element (PTE) has posed remarkable ecological risks to environment. Application of functionalized biochar for the remediation of PTE contaminated water and soils are of great concern, and effective strategies are urgently needed to enhance the removal capacity of biochar for PTE. As a novel surface modification technology, the effect of layered double hydroxides (LDH) and sodium dodecyl sulfonate (SDS) on the remediation capacity of biochar for PTE polluted soils and water remains unclear. Sawdust biochar (SB) was coated with Mg and Fe to synthesize the Mg-Fe-LDH functionalized biochar (MFB); thereafter, the MFB was mixed with SDS solution to synthesize the organic-Mg-Fe-LDH biochar (MSB). The potential of SB, MFB, and MSB for remediation of Cd and Pb contaminated soil and water was evaluated in terms of adsorption capacity, immobilization efficiency, and stability. Loading of Mg-Fe-LDH into SB, along with SDS treatment created a regular micro-nano hierarchical structure and enhanced the surface roughness, aromaticity, and hydrophobicity of MSB as compared to SB. MSB exhibited a significantly higher maximum adsorption capacity (mg g−1) for water Pb (405.2) and Cd (673.0) than MFB (335.9 for Pb and 209.0 for Cd) and SB (178.2 for Pb and 186.1 for Cd). MSB altered the soluble fraction of Cd/Pb to the residual fraction and thus significantly decreased their mobilization in soil. The higher removal/immobilization efficiency of MSB could be attributed to its alkalinity, and the enhanced synergistic interactions including surface precipitation, ion exchange, complexation, and hydrogen bonding. The resistance to carbon loss by H2O2, thermal recalcitrance index R50, and degree of graphitization in MSB were significantly improved compared to SB, indicating a more stable carbon fraction sequestered in MSB following aging in soil. These results indicate that MSB could be used for remediation of Cd and Pb contaminated soil and water.Graphical