Recent trends and economic significance of modified/functionalized biochars for remediation of environmental pollutants

A valorization analysis towards agricultural application of biochar prepared using maize straw grown using organic or chemical fertilizers

To assess the potential of biochar-based fertilizers, this study applied 200 kg N hm-2, 180 kg P2O5 hm-2, and 180 kg K2O hm-2 for maize straw cultivation using either organic or chemical fertilizers. The resulting biochar from both treatments was analyzed. Findings indicated an increase in total carbon (C) content, pH, and mean residence time (MRT) with rising pyrolysis temperatures (300-700 °C). Biochar derived from chemically fertilized maize demonstrated higher total C content and MRT (61.3-74.4 wt% and 232.5-1473.6 year, respectively) compared to that from organically fertilized maize (54.7-59.1 wt% and 126.7-714.5 year, respectively). Potassium (43.6-113.8 g kg-1) and phosphorus (9.5-12.3 g kg-1) contents were notably higher in biochar from organic fertilizer. All biochar samples were generally higher in the organic fertilizer biochar than in the chemical fertilizer biochar (14.5-49.6 g kg-1 and 5.5-10.5 g kg-1, respectively) and met industry standard of biochar-based organic fertilizer (NY/T 3618-2020). Biochar from both fertilization methods, pyrolyzed at 500 °C, can serve as nutrient carriers and facilitate C sequestration in soil.

Optimizing CO2 capture: Effects of chemical functionalization on woodchip biochar adsorption performance

As atmospheric CO2 concentrations rise, primarily due to fossil fuel combustion and deforestation, the urgent need for effective carbon capture solutions becomes increasingly critical to mitigate global warming. This study investigates the enhancement of CO2 adsorption in woodchip biochar (WBC) through targeted chemical functionalization with potassium hydroxide (KOH), sodium hydroxide (NaOH), and ferrous sulfate (FeSO4). Using Central Composite Design (CCD) and Response Surface Methodology (RSM), it is systematically possible to identify optimal functionalization conditions to maximize the biochar's adsorption efficiency. The KOH-treated biochar exhibited the highest adsorption capacity (Qmax of 9.89 mmol/g), substantially improving over untreated biochar (Qmax of 4.54 mmol/g). Adsorption analysis through Langmuir and Freundlich isotherm models highlighted a strong alignment with the Langmuir model, suggesting a predominantly monolayer adsorption surface. Additionally, kinetic studies using pseudo-first-order (PFO) and pseudo-second-order (PSO) models indicated a favourable chemisorption process, with the PSO model showing a superior fit. These results demonstrate the potential of chemically functionalized biochar, especially when treated with KOH, as a viable material for CO2 capture, presenting an environmentally sustainable pathway for addressing the pressing issue of atmospheric CO2. Utilizing biochar derived from organic waste also promotes waste valorisation and supports a circular economy. Optimised biochar could mitigate CO2 emissions, potentially serving as a complementary solution in climate change mitigation strategies, especially in scenarios where biochar can be deployed at scale in industrial or agricultural settings.

Recent advances in valorization of lignocellulosic waste into biochar and its functionalization for the removal of chromium ions

Lignocellulosic waste is a prevalent byproduct of agricultural and forestry activities which is an excellent feedstock for the preparation of biochar. This research area is of interest to the scientific community due to its potential in environmental remediation. In this regard, this review examines the latest advancements in transforming lignocellulosic waste into biochar and explores recent innovations in enhancing its functionality for chromium ion removal. It gives analysis on current methods for biochar production from lignocellulosic materials such as pyrolysis. Additionally focusing on improvements in production efficiency, structural properties, and surface modifications. The review also highlights various functionalization techniques, such as chemical activation and impregnation with metal oxides, that were innovated to improve adsorptive nature of biochar for chromium ions. While progress has been made, achieving scalability in lignocellulosic biochar production presents challenges, such as the high energy demands of pyrolysis, inconsistencies in feedstock quality, and the need for cost-effective functionalization methods. By summarizing recent research and technological progress, this paper aims to offer a clear perspective on the effectiveness of biochar derived from lignocellulosic waste in addressing contamination. Additionally, it discusses the ongoing challenges and future research directions needed to optimize biochar applications in environmental cleanup.

De-ashed-biochar slow-release N fertilizer increased NUE in alkaline calcareous soils under wheat and maize crops

Recently biochar has widely been reported as carrier of SRFs. However, the performance of SRFs synthesized from pristine biochar is still low and could not achieve the significant benefits compared to conventional N fertilizers. To overcome this limitation and research gap, BSRFs were synthesized using modified / de-ashed biochar as N-carrier. We hypothesized that BSRFs would NUE especially in alkaline calcareous soils for whom there is no specific SRF exist previously. In this study, the efficacy of BSRF formulated with 1:1 mass ratio of de-ashed biochar and urea was compared with CU and CSRF for improving NUE under wheat (Triticum aestivum L.) and maize (Zea mays L.) cropping system in two different textured soils. The results showed that compared to CU and CSRF, the addition of BSRF significantly increased the retention of soil mineral-N (NH4+-N, NO3--N) which, consequently, enhanced the crops' N-uptake up to 23.71% in wheat and 26.55% in maize. It was further observed that SOC contents were increased up to 50.79% in wheat and up to 47.61% in maize at harvest. The addition of BSRF enhanced the CEC up to 32.95% under wheat and up to 27.73% under maize, compared to CU. Eventually, BSRF significantly increased the grain yield and NUE of wheat by 12.04% and 40.44%, while the maize grain yield and NUE increased by 21.06% and 45.56%, respectively. This study concludes that BSRFs had a stronger yield-increasing effect than CU alone attributing to enhanced N retention and crop uptake in alkaline calcareous soils. It was also found that the de-ashed biochar is a strong candidate to formulate new SRFs with improved performance.

Effective removal of As5+ from aqueous medium using date palm fiber biochar/chitosan/glutamine nanocomposite: kinetic and thermodynamic studies

In the current work, three adsorbent materials were developed: biochar derived from date palm fiber (C), date palm fiber biochar/chitosan nanoparticles (CCS), and biochar/chitosan nanoparticle composite supplemented with glutamine (CCSG). These compounds were used as solid adsorbents to remove As5+ from polluted water. Several characterization approaches were used to investigate all the synthesized solid adsorbents, including thermogravimetric analysis, N2 adsorption/desorption isotherm, scanning electron microscopy, transmission electron microscopy (TEM), attenuated total reflectance with Fourier transform infrared, and zeta potential. Date palm fiber biochar/chitosan/glutamine nanocomposite (CCSG) demonstrated good thermal stability, with a maximum specific surface area of 518.69 m2/g, a mesoporous size of 2.06 nm, total pore volume of 0.25 cm3/g, TEM average particle size of 38 nm, and pHPZC of 6.9. Contact time (5-60 min), pH (1-9), starting As5+ concentration (50-500 mg/L), adsorbent dose (0.1-2.0 g/L), temperature (27-45 °C), and ionic strength (0.05-0.40 mol/L) were among the sorption parameters that were investigated in order to improve the adsorption conditions. It is observed that the modified samples were effectively able to remove As5+ (CCS; 256.0 and CCSG; 376.0 mg/g) than unmodified ones (C; 150.5 mg/g). The As5+ removal procedure corresponded well with Langmuir isotherm model. Thermodynamic and kinetic experiments show that the Elovich, pseudo-first order, and Van't Hoff plot with endothermic, spontaneous, and physisorption nature are the best fitted models. EDTA has the highest desorption efficiency percentage (98.8%). CCSG demonstrated enhanced reusability after six application cycles of As5+ adsorption/desorption, with only a 4% decrease in the efficiency of adsorption. This work shows that adding glutamine to the DPF biochar/chitosan composite reinforces it, resulting in the fabrication of a solid adsorbent that shows promise for use in water remediation.

Integrating spatial-temporal features into prediction tasks: A novel method for identifying the potential water pollution area in large river basins

Forecasting potential water pollution areas (PWPA) is essential for effective watershed management. However, there remains a limited understanding of the spatial-temporal features that influence water quality (WQ), and advanced technical methods for WQ forecasting. This study developed an integrated framework utilizing spatial-temporal graph convolution networks (STGCN) to enhance comprehension of the spatial-temporal features influencing WQ and to develop a practical module for integrating features into the WQ prediction. The Pearson correlation method and seasonal decomposition analysis described the WQ features. Subsequently, the spatial-temporal distribution of PWPA was assessed using both the comprehensive pollution index method and Cressman space interpolation technique. Data from 403 monitoring stations was collected from the Yangtze River basin (YZR), encompassing pollutants such as COD, TP and NH₄⁺-N. The finding revealed that maximum concentrations of COD (36.4 mg/L), TP (4.078 mg/L) and NH₄⁺-N (13.58 mg/L) exceeded the standard thresholds necessitating early warnings. A significant correlation among pollutants was observed with coefficients ranging from 0.356 to 0.475 (P < 0.001), indicating their potential utility in predicting PWPA. Seasonality components exhibited strong correlations with the original WQ (correlation coefficients ranging from 0.62 to 0.89), followed by residuals (from 0.37 to 0.61) and trend components (from 0.25 to 0.53). The geographic layout of WQ monitoring stations along river lines resembled a graph network structure, suggesting that watershed WQ prediction can be classified as a spatial-temporal prediction task. The STGCN model achieved R2 values ranging from 0.607 to 0.844 for each pollutant on the test datasets, surpassing traditional models such as RNN, LSTM, and GRU in predictive accuracy. PWPA occurrences were predominantly identified in the southwestern regions as well as within the middle and lower reaches of the YZR. These results validated that the developed framework is capable of forecasting PWPA in large-scale watersheds while supporting effective watershed management.

Impact of Acacia-derived biochar to mitigate salinity stress in Zea mays L. by morpho-physiological and biochemical indices

Climate change has caused many challenges to soil ecosystems, including soil salinity. Consequently, many strategies are advised to mitigate this issue. In this context, biochar is acknowledged as a useful addition that can alleviate the detrimental impacts of salt stress on plants. The objective of this study is to evaluate the effects of different levels of salt (Control; T0 0 gl-1, T1; 1.50, and T2; 3 gl-1) and biochar addition rates (A0; 0 g kg-1, A1; 40 g kg-1, and A2; 80 g kg-1) on the agronomic, physiological, and biochemical responses of corn plants. The results of our study showed a significant increase in the biomass of corn plants when exposed to salt stress and treated with 40 g kg-1 of biochar. The result underscores the significant function of Acacia-biochar in mitigating salt toxicity. The application of A1 biochar at a specified rate mitigated the adverse effects of salt-induced oxidative stress by augmenting the activities of catalase (CAT) and glutathione-S-transferase (GST). Furthermore, the utilization of biochar led to an increase in chlorophyll b concentrations in maize plants subjected to saline water treatment. Biochar is generally considered an efficient method for alleviating the adverse effects of salinity. To enhance plant growth and development while mitigating salinity-induced toxicity, the application of biochar in saline soils must be implemented appropriately.

Optimizing the dual role of biochar for phosphorus availability and arsenic immobilization in soils

Soil Phosphorus (P) fixation and Arsenic (As) contamination pose significant challenges to agriculture and environmental health. Biochar has emerged as a promising soil amendment capable of enhancing P availability while immobilizing As. This review explored the mechanisms by which biochar influences P dynamics and As sequestration. Biochar enhances P availability by reducing fixation, stimulating P-solubilizing microorganisms, and gradually releasing the adsorbed P. Specific biochars, such as Mg-modified and La-modified types, demonstrate high P adsorption capacities, reaching up to 263 mg/g, while cerium and iron-modified biochars show As adsorption efficiencies up to 99 % under certain conditions. Biochar's surface functional groups are essential for P and As adsorption through mechanisms such as surface adsorption, ligand exchange, and inner-sphere complexation. The competitive adsorption between P and As is influenced by pH, biochar modification, and co-existing anions. Under acidic conditions, As shows a higher affinity for biochar, forming stable complexes with metal oxides like iron and aluminum. Biochars modified with calcium, magnesium, lanthanum, zinc, cerium, and iron demonstrate enhanced adsorption capacities. In neutral to alkaline conditions, calcium- and magnesium-modified biochars benefit P retention, while iron-modified biochar is preferable for As adsorption. Additionally, biochar promotes microbial activity and enzymatic processes that facilitate As transformation and P mineralization, enhancing overall soil health. These findings underscore biochar's dual role in increasing nutrient availability and reducing contaminant risks, making it a valuable tool for sustainable agriculture. Field-scale applications should be prioritized in future research to optimize biochar's impact on soil fertility and environmental remediation.

Self-assembly of ZnO-Biochar/Kaolinite/Chitosan/GO with 1D/2D/3D heterojunctions for enhanced removal of estrogens and triclosan in water

This Study focuses on the preparation of sustainable and efficient Chitosan catalyst for the removal of three organic pollutants, 17β-Estradiol (E2), 17α-ethynyl estradiol (EE2) and triclosan (TCS) from water. The prepared nanocomposites were characterized by different techniques which confirmed the presence of the key components Chitosan, Carica Papaya seed and Kaolinite. The optical characterization proved the nanocomposite is photoactive with a band gap of 1.81 eV and 1.77 eV for Chitosan/kaolinite biochar (CS/KBC) and Chitosan/kaolinite biochar/GO (CS/KBC/GO) respectively, confirming the ability of the nanocomposite to be active in the visible light region of the spectrum. The degradation experiment using CS/KBC/GO was observed better with 100% removal for 5 mg/L E2 and EE2 over 60 min and 97.8% over 120 min for 10 mg/L TCS at optimum conditions (pH 3 for E2, and EE2 and pH 7). It was observed that the superoxide radical played a major role in the degradation of the contaminants. Furthermore, the CS/KBC/GO was efficient over four cycles without any decrease in performance, which rules out the question of catalyst deactivation proving the sustainability of the catalyst. The toxicity test shows that the water is safe as it does not harm cerio daphnia silvestrii organism.; CS/KBC/GO efficiently removed the micropollutants from real-life waste samples and the performance was very good with a slight decrease in performance for the wastewater due to the complex matrix of the water sample that competes for the active site.

Biochar-based fixed filter columns for water treatment: A comprehensive review

Biochar used in fixed filter columns (BFCs) has garnered significant attention for its capabilities in material immobilization and recovery, filtration mechanisms, and potential for scale-up, surpassing the limitations of batch experiments. This review examines the efficacy of biochar in BFCs, either as the primary filtering material or in combination with other media, across various wastewater treatment scenarios. BFCs show high treatment efficiency, with an average COD removal of 80 % ±15.3 % (95 % confidence interval: 72 %, 86 %). Nutrient removal varies, with nitrogen-ammonium and phosphorus-phosphate removal averaging 71 ± 17.1 % (60 %, 80 %) and 57 % ± 25.6 % (41 %, 74 %), respectively. Pathogen reduction is notable, averaging 2.4 ± 1.12 log10 units (1.9, 2.9). Biochemical characteristics, pollutant concentrations, and operational conditions, including hydraulic loading rate and retention time, are critical to treatment efficiency. The pyrolysis temperature (typically 300 to 800 °C) and duration (1.0 to 4.0 h) influence biochar's specific surface area (SSA), with higher temperatures generally increasing SSA. This review supports the biochar application in wastewater treatment and guides the design and operation of BFCs, bridging laboratory research and field applications. Further investigation is needed into biochar reuse as a fertilizer or energy source, along with research on BFC models under real-world conditions to fully assess their efficacy, service life, and costs for practical implementation.

A cutting-edge approach to remove arsenic contents from ground water via sulfur doped copper ferrites (S-CuFe2O4) †

Pure water is necessary for healthy life; however natural ground water has many toxic metals. Before drinking, it must be free from toxic metals that commonly causes cancer. For example, arsenic is hazardous element but unfortunately it is naturally present in ground water. Due to its high solubility, removal of arsenic from water is not easy. In recent decades, presence of arsenic in ground water has been reported in many areas of Pakistan. Purpose of current project is to estimate and eliminate arsenic contents from the ground drinking water of Tribal Belt of DG Khan. For the comprehensive survey, 200 water samples were collected from the areas where large proportion of ground water is being consumed for drinking. In this work, relatively cheaper and effective adsorbent namely S‒CuFe2O4 have been synthesized for the quick removal of arsenic. Arsenic contents were converted to the arsenomolybdate complex (AMC) and this complex was then adsorbed on S‒CuFe2O4. Morphology and chemical characteristics have been evaluated via XRD, SEM, FT-IR, Raman, TGA, EDX, AFM and XPS techniques. Additionally, various kinetic models were employed to confirm and validate the adsorption phenomena. Based on the results and assessment, it has been concluded that 1.5 g of aforementioned adsorbent is adequate to deliver 432 gal of arsenic free water.

Sugarcane bagasse-derived biochar modified by alkali for enriching surface functional groups to effectively treat ammonium-contaminated water

In this study, sugarcane bagasse (SB), which was preliminarily treated with H3PO4, was utilized to produce biochar (SB-BC). The SB-BC was subsequently modified with KOH to enrich oxygen-containing functional groups (OCFGs) for the enhanced adsorption of NH4+ from wastewater. Batch tests revealed that KOH-modified SB-BC (SB-MBC) increased the maximum Langmuir adsorption capacity of NH4+ by approximately twofold, from 27.1 mg/g for SB-BC to 53.1 mg/g for SB-MBC. The optimal operational conditions for NH4+ adsorption onto SB-MBC were pH of 7.0 and a biochar dose of 3.0 g/L for the removal of 50 mg/L NH4+ at room temperature (25 ± 2 °C) over 180 min of contact. The enhanced adsorption capacity of NH4+ onto SB-MBC was due to the important contribution of the OCFGs enriched on the surface of biochar, which was increased by about fourfold, after being modified by KOH. The NH4+ adsorption dynamics were better fitted by the Elovich and the NH4+ adsorption isotherms were better described by Langmuir and Sips models, showing that the adsorption process was dominated by monolayer chemisorption. The properties of the adsorption materials before and after adsorption of NH4+ confirmed that cation exchange, electrostatic attraction and surface complexation were the main mechanisms controlling the adsorption process. The desorption and reusability tests of NH4+-saturated SB-MBC revealed that NH4+ adsorption slightly decreased after three successive sorption‒desorption cycles. The findings suggested that SB-MBC is a promising and feasible adsorbent for the effective treatment of NH4+-contaminated water sources. Future work should conduct tests for treatment of NH4+-rich real wastewater and utilize NH4+-saturated SB-MBC as slow releasing fertilizer for plants growth.

A simulation-based analysis of optical read-out for electrochemical reactions using composite vortex beams

We propose an optical read-out method for extracting faradaic current in electrochemical (EC) reactions and analyze its performance using opto-EC simulations. Our approach utilizes structured electrodes to generate composite optical vortex (COV) beams upon optical illumination. Through opto-EC simulations, we demonstrate that the EC reaction of 10 mM potassium ferricyanide induces a refractive index (RI) change, Δ RI, of approximately 10 - 4 RI units, leading to the rotation of the COV beam's intensity profile with a peak rotation of 40 ∘ . This rotation's magnitude is proportional to Δ RI, while the rate correlates with the faradaic current ( I f ) density responsible for Δ RI. As the opto-EC information is from bulk Δ RI, it remains unaffected by interfering non-faradaic components at the interface and is advantageous for studying intermediate species and bulk homogeneous reactions. Furthermore, as rotation depends on I f density rather than I f itself, this method proves beneficial in low I f scenarios, such as when employing micro-electrodes to decrease solution resistance or obtain localized EC data. Even in low I f density scenarios, like monitoring slow EC reactions, our method enables signal amplification by accumulating rotation over time. This interdisciplinary approach holds promise for advancing EC research and addressing critical challenges across various fields, including energy storage, corrosion protection, environmental remediation, and biomedical sciences.

Evaluation of optimized conditions for the adsorption of malachite green by SnO2-modified sugarcane bagasse biochar nanocomposites

This work deals with the synthesis of SnO2-modified sugarcane bagasse biochar (SnO2-SBB) nanocomposites using an impregnation method. XRD, FTIR, SEM, and EDX analyses were used to characterize the produced nanocomposites. Several factors influencing the removal of malachite green from wastewater via the adsorption process were explored to maximize the effectiveness of this process. These factors included the different doses of nanocomposites, pH, temperature, contact time, etc. Studies on batch adsorption were conducted to examine the impact of operational parameters, such as contact time (5 to 30 minutes), adsorbent dosage (5 to 40 mg), pH (2 to 10), and temperature (303, 323, and 353 K), on the percentage of MG dye removal. The adsorption kinetics of MG dye over SnO2-SBB nanocomposites were evaluated with the aid of the Langmuir adsorption isotherm, which provided a good fit (R 2 = 0.99) for pseudo-second-order kinetics. The thermodynamic parameters revealed spontaneous and exothermic adsorption of MG dye over SnO2-SBB nanocomposites. A maximum adsorption capacity (q max) of 52.64 ± 0.03 for 0.3 SnO2-SBB and 73.86 ± 0.05 for 0.5 SnO2-SBB nanocomposites was observed. The newly synthesized SnO2-SBB nanocomposites showed negative zeta potential, which facilitated the adsorption of hydrated cationic dye molecules due to the electrostatic force of attraction.

Biogenic mediated green synthesis of NiO nanoparticles for adsorptive removal of lead from aqueous solution

The spread of heavy metal in water bodies, particularly lead (Pb), has occurred as a global threat to human existence. In this study, NiO nanoparticles (NPs) was prepared by coprecipitation approach using Hagenia abyssinica plant extract mediated as a reducing and template agent for the removal of Pb from aqueous solution. X-ray crystallographic diffraction (XRD), Scanning electron microscopy (SEM), Fourier transform infrared (FTIR), and Brunauer-Emmett-Teller (BET) techniques were employed for the characterization of as prepared NiO NPs. The efficacy of adsorbent was evaluated on the removal of Pb2+ by varying the adsorptive parameters such as pH, Bio-NiO amount, interaction time, and Pb2+ concentration. The adsorption was 99.99% at pH, 0.06 g of NiO NPs dose, 60 mg L-1 concentrations of Pb2+ within 80 min contact time. The higher removal efficiency is could be due to higher surface area (151 m2g-1). The adsorption process was best fitted with Freundlich isotherm and pseudo-second order kinetic models, implying that it was chemical adsorption on the heterogeneous surface. The adsorption intensity (n) was found to be 1/n < 1 (0.47) indicating adsorption of Pb2+ on the surface of Bio-NiO NPs was favorable with a maximum adsorption capacity 60.13 mg g-1. The reusability studies confirmed that the synthesized bio-NiO NPs were an effective adsorbent for removing Pb2+ from aqueous solution up to five cycles.

Fabrication of engineered biochar for remediation of toxic contaminants in soil matrices and soil valorization

Biochar has emerged as an efficacious green material for remediation of a wide spectrum of environmental pollutants. Biochar has excellent characteristics and can be used to reduce the bioavailability and leachability of emerging pollutants in soil through adsorption and other physico-chemical reactions. This paper systematically reviewed previous researches on application of biochar/engineered biochar for removal of soil contaminants, and underlying adsorption mechanism. Engineered biochar are derivatives of pristine biochar that are modified by various physico-chemical and biological procedures to improve their adsorption capacities for contaminants. This review will promote the possibility to expand the application of biochar for restoration of degraded lands in the industrial area or saline soil, and further increase the useable area. This review shows that application of biochar is a win-win strategy for recycling and utilization of waste biomass and environmental remediation. Application of biochar for remediation of contaminated soils may provide a new solution to the problem of soil pollution. However, these studies were performed mainly in a laboratory or a small scale, hence, further investigations are required to fill the research gaps and to check real-time applicability of engineered biochar on the industrial contaminated sites for its large-scale application.

Investigating the growth promotion potential of biochar on pea (Pisum sativum) plants under saline conditions

Pea, member of the plant family Leguminosae, play a pivotal role in global food security as essential legumes. However, their production faces challenges stemming from the detrimental impacts of abiotic stressors, leading to a concerning decline in output. Salinity stress is one of the major factors that limiting the growth and productivity of pea. However, biochar amendment in soil has a potential role in alleviating the oxidative damage caused by salinity stress. The purpose of the study was to evaluate the potential role of biochar amendment in soil that may mitigate the adverse effect of salinity stress on pea. The treatments of this study were, (a) Pea varieties; (i) V1 = Meteor and V2 = Green Grass, Salinity Stress, (b) Control (0 mM) and (ii) Salinity (80 mM) (c) Biochar applications; (i) Control, (ii) 8 g/kg soil (56 g) and (iii) 16 g/kg soil (112 g). Salinity stress demonstrated a considerable reduction in morphological parameters as Shoot and root length decreased by (29% and 47%), fresh weight and dry weight of shoot and root by (85, 63%) and (49, 68%), as well as area of leaf reduced by (71%) among both varieties. Photosynthetic pigments (chlorophyll a, b, and carotenoid contents decreased under 80 mM salinity up to (41, 63, 55 and 76%) in both varieties as compared to control. Exposure of pea plants to salinity stress increased the oxidative damage by enhancing hydrogen peroxide and malondialdehyde content by (79 and 89%), while amendment of biochar reduced their activities as, (56% and 59%) in both varieties. The activities of catalase (CAT), superoxide dismutase (SOD), and peroxidase (POD) were increased by biochar applications under salinity stress as, (49, 59, and 86%) as well as non-enzymatic antioxidants as, anthocyanin and flavonoids improved by (112 and 67%). Organic osmolytes such as total soluble proteins, sugars, and glycine betaine were increased up to (57, 83, and 140%) by biochar amendment. Among uptake of mineral ions, shoot and root Na+ uptake was greater (144 and 73%) in saline-stressed plants as compared to control, while shoot and root Ca2+ and K+ were greater up to (175, 119%) and (77, 146%) in biochar-treated plants. Overall findings revealed that 16 g/kg soil (112 g) biochar was found to be effective in reducing salinity toxicity by causing reduction in reactive oxygen species and root and shoot Na+ ions uptake and improving growth, physiological and anti-oxidative activities in pea plants (Fig. 1). Figure 1 A schematic diagram represents two different mechanisms of pea under salinity stress (control and 80 mM NaCl) with Biochar (8 and 16 g/kg soil).

A review on sustainable management of biomass: physicochemical modification and its application for the removal of recalcitrant pollutants-challenges, opportunities, and future directions

Adsorption is one of the most efficient methods for remediating industrial recalcitrant wastewater due to its simple design and low investment cost. However, the conventional adsorbents used in adsorption have several limitations, including high cost, low removal rates, secondary waste generation, and low regeneration ability. Hence, the focus of the research has shifted to developing alternative low-cost green adsorbents from renewable resources such as biomass. In this regard, the recent progress in the modification of biomass-derived adsorbents, which are rich in cellulosic content, through a variety of techniques, including chemical, physical, and thermal processes, has been critically reviewed in this paper. In addition, the practical applications of raw and modified biomass-based adsorbents for the treatment of industrial wastewater are discussed extensively. In a nutshell, the adsorption mechanism, particularly for real wastewater, and the effects of various modifications on biomass-based adsorbents have yet to be thoroughly studied, despite the extensive research efforts devoted to their innovation. Therefore, this review provides insight into future research needed in wastewater treatment utilizing biomass-based adsorbents, as well as the possibility of commercializing biomass-based adsorbents into viable products.

Advancements in application of modified biochar as a green and low-cost adsorbent for wastewater remediation from organic dyes

Synthetic organic dyes, which are resistant to biodegradation, pose a notable health risk, potentially leading to cancer and respiratory infections. Researchers have addressed this concern by exploring physicochemical methods to remove organic dyes from wastewater. A particularly promising solution involves modified biochar adsorbents, which demonstrate high efficiency in organic dye removal. Biochar, a charcoal-like material derived from biomass pyrolysis, offers advantages such as low cost, eco-friendliness, high efficiency and reusability. Beyond its role in sustainable soil remediation, biochar proves effective in removing organic dyes from wastewater after undergoing physical or chemical modification. Acid-base activation or metal-heteroatom impregnation enhances biochar's adsorption capacity. This comprehensive review examines the attributes of biochar, common methods for production and modification, and the impacts of raw materials, pyrolysis temperature, heating rate and residence time. It further elucidates the biochar adsorption mechanism in the removal of organic dyes, assessing factors influencing efficiency, including biochar feedstock, solution pH, adsorption temperature, particle size, initial dye concentration, biochar dosage and reaction time. It explores challenges, opportunities, reusability and regeneration methods of biochar in treating organic dye wastewater. It also discusses recent advances in organic dye removal using adsorption-based biochar. The review ultimately advocates for enhancing biochar's adsorption performance through post-modification.