Following the design concept of high efficiency, environmental friendliness, and stable performance, the application of an electrodeposition-capacitive deionization combined process for copper removal from highconcentration wastewater is the first time proposed in this study. As a pretreatment, electrodeposition exhibited efficient copper ions removal capacity (94.53 %) within only 80 min, and the optimal operation conditions were obtained as 75 mA/cm2 current density, 1.5 cm electrode spacing, pH value 4, and 1000 mg/L initial copper ion concentration. The electrodeposit predominantly consisted of Cu0 with minor copper oxide impurities was characterized and can be reintroduced into the production process as a valuable raw material. Subsequently, the wastewater underwent advanced treatment via capacitive deionization technology, resulting in the final copper ion concentration of 0.43 mg/L, which met the discharge limit of criteria (GB 39731-2020, less than 0.5 mg/L). The experimental results demonstrate that the combined process is feasible for treating high-concentration copper-containing wastewater, thereby offering a new technological pathway for the efficient wastewater treatment and resource recovery.

The coactivation of biomass using different metal salts remains underexplored despite its potential to engineer hierarchical porosity in biochar. Herein, we report a sustainable and innovative strategy for converting bamboo waste into meso/microporous biochar (MMB) through simultaneous activation with K2CO3 and CaCO3. The resulting MMB features a high specific surface area of 1811.31 m2/g and a total pore volume of 1.01 cm3/g. When evaluated for diethyl phthalate removal, MMB achieves a maximum sorption capacity of 930.56mg/g according to the Sips model, considerably exceeding those of conventional biochars and commercial activated carbons. More importantly, MMB also demonstrates high performance toward sulfamethoxazole, a representative antibiotic, with a maximum sorption of 676.27mg/g according to the Sips model. Mechanistic analyses reveal that pore filling, hydrophobic partitioning, hydrogen bonding, and π–π stacking collectively govern the sorption of organic pollutants. Furthermore, MMB exhibits excellent reusability over five cycles, growth-stimulating properties, and robust performance in real water matrices (tap water, lake water, and domestic sewage). The preliminary material-and-energy cost of MMB is estimated to be 9.52 $/kg, which is lower than that of activated carbon prepared via KOH activation. This coactivation paradigm offers a facile, cost-effective, and scalable route for upgrading biowaste into high-performance sorbents, addressing the simultaneous challenges of emerging pollutant remediation and waste valorization.

The proper disposal and recycling of dredging sludge remain a global challenge. In this study, response surface methodology was applied to optimize the preparation conditions of non-sintered sludge based materials with phosphorus-containing waste sludge as the raw material. The non-sintering process converted unstable phosphorus into stable forms, achieving effective endogenous phosphorus fixation. The Thomas model well described the dynamic phosphorus adsorption process. Moreover, the CWs system reached a TP removal efficiency of 82.2% with non-sintered sludge based materials and Phragmites australis. Furthermore, the responses of soil enzymes, microbial communities, and soil physiochemical properties to the combined effects of non-sintered sludge based material addition and Phragmites australis cultivation, as well as the associated changes in substrate configuration were investigated. Specifically, the application of non-sintered sludge based materials as well as the associated changes in substrate configuration created a phosphorus-deficient environment, which promoted the growth of phosphate-solubilizing bacteria and regulated Phragmites australis roots to secrete more phosphorus activation factors (organic acids, alkaline phosphatase and phytase). As a result, fixed soil phosphorus was solubilized, and available phosphorus concentration increased from 11.18 mg/kg to 31.59 mg/kg to support Phragmites australis growth. The findings offered preliminary insights into the resource utilization of waste sludge and the remediation of phosphorus pollution in CWs with significant practical application potential.

The large-scale discharge of Na+-rich wastewater has intensified the global freshwater crisis. Flow-electrode capacitive deionization (FCDI) offers a promising electrosorption technology for desalination. Lignin is the representative by-product of the papermaking industry, and lignin-derived biochar has been intensively investigated as an active material for flow-electrode material. In this study, we proposed a facile dual-salt (KCl and LiCl) catalysis method during hydrothermal carbonization to prepare lignin-derived biochar (Li-K-LCN). The characterization results showed that the dual-salt catalysts exerted combined effect by physical structure optimization and surface chemical modification based on the cleavage of low bond energy moieties (beta-O-4 ether bond and methoxyl group) in the lignin structure. When employed in a flow-electrode capacitive deionization (FCDI) system for Na+ removal, Li-K-LCN electrode achieved a stable removal efficiency of over 83.3%, an electrosorption capacity of 26.03 mg g-1, and low energy consumption of 0.015 J mg-1. Toxicity tests indicated a preliminary favorable improvement in the environmental safety of the treated effluent. This work presented a simple and efficient dual-salt catalysis method to synthesize lignin-derived biochar towards competitive Na+ removal via FCDI, achieving the goal of a low-cost, high-value-added by-product lignin utilization.

Biomass-derived porous biochars perform exceptionally well in various fields due to their highly developed pore structures and low cost. Existing preparation methods lack diversity, limiting the ability to tailor pore architectures. This study introduces an innovative sequential activation method that uses different activating agents on biowaste to produce nanopore-rich porous biochars (NPBs). Using bamboo biomass, activation with calcium carbonate followed by potassium carbonate yielded NPBs with a well-developed pore network containing abundant mesopores and micropores, a specific surface area of 2061 m2/g, and a pore volume of 1.16 cm3/g. After two high-temperature activation steps, NPBs showed reduced oxygen content, increased hydrophobicity, and the formation of graphite-like structures. NPBs can rapidly remove emerging contaminants from water-including the plasticizer diethyl phthalate (652 mg/g) and the antibiotic sulfamethoxazole (689 mg/g)-exceeding the capacities of most reported sorbents. The primary sorption mechanisms involved pore filling, partitioning, π-π stacking, and hydrogen bonding. While phosphate ions interfered with sorption, other common coexisting solutes had limited effects, and NPBs performed well in real water samples. Seed germination tests revealed minimal short-term impacts on plant growth, with some promotion of stem elongation. This study presents a tunable strategy for porous carbon synthesis, with the derived products showing promise for applications in environmental remediation, energy, healthcare, and beyond.

Artificial humic acids (AHAs) exhibit superior performance in enhancing crop yields and promoting environmental remediation. However, research into the compositional and property differences of AHAs derived from diverse real-world biowastes remains inadequate, thereby hindering their controlled preparation and practical applications. To address this gap, this study utilized a multifaceted analytical approach, notably incorporating electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI-FT-ICR-MS), to systematically elucidate the molecular-level heterogeneity of AHAs from a specific set of real-world biowastes and link this diversity back to the composition of their precursors. AHAs produced from diverse precursors via hydrothermal humification consistently exhibited low yields and shared similarities in their functional groups and thermal stability. In contrast, fluorescence spectroscopy analysis revealed distinct fluorescent components and intensities, such as fulvic acid-like substances. ESI-FT-ICR-MS analysis revealed up to 2000 molecular compositional differences among the different AHAs, which were primarily attributed to CHON compounds. Lignin/CRAM-like compounds constituted the major components and were the primary determinants of AHAs heterogeneity. Compared with other AHAs, those derived from invasive plants presented greater heterogeneity, characterized by a lower molecular weight, reduced aromaticity, and a greater abundance and diversity of heteroatoms. Notably, substantial AHAs yields and significant molecular diversity were achieved even from precursors with low lignin, cellulose, and hemicellulose contents. This study provides a molecular-scale perspective on the similarities and differences in AHAs, offering new insights into their controlled synthesis and understanding their environmental behavior.

The uprecycling of hydrothermal liquid waste-derived artificial humic acids into stable carbon materials is helpful for advancing the development of hydrothermal carbonization technology, but it has rarely been investigated. For the first time, a multistep pyrolysis method was designed to convert artificial humic acids into honeycomb-like porous carbons (PCs). The obtained PCs exhibited a high specific surface area, reaching 1728.55 m2/g, while nonactivation treatment still provided a high value of 1425.14 m2/g. The hightemperature pyrolysis process yielded graphite-like structures and maintained surface functional groups. PCs have been applied as sorbents to remove the emerging plasticizer diethyl phthalate (DEP) in water environments and exhibit promising sorption capabilities (as high as 993.30 mg/g), which are much higher than those reported for other sorbents. The sorption rate was controlled by mass transfer and chemical-like sorption, whereas the sorption capability was controlled mainly by the adsorption process, especially pore filling. Partitioning, hydrogen bonding, pore filling and it-it stacking are possible sorption mechanisms. In addition to the specific surface area, the pore volume is a suitable parameter for assessing the sorption capability. Exogenous dissolved organic matter can affect the sorption of DEP onto PCs through cosorption and coverage of their surface, but its influence is limited. Excellent sorption performance can cover a wide range of pH conditions. The prepared PCs also showed notable reusability and practicality. In this study, an excellent method was proposed for recycling hydrothermal liquid waste and preparing PCs, and the prepared PCs exhibited great potential for environmental remediation.

Flow-electrode capacitive deionization (FCDI) can be a promising technology for fluorine removal from groundwater. In this study, a new kind of titanium (IV) hydroxide modified biochar (Ti-BC) was prepared by a simple method and used as FCDI electrode materials to selectively remove F- at the first time. Ti-BC exhibited superior defluorination capabilities due to the its unique mesoporous structure and the introduction of hydroxyl functional groups. The optimal F- removal performance was obtained by optimizing the operation parameters and the parameter of applied voltage had the greatest impact. Ti-BC electrode performed excellent electrosorption capacity of 9.65 mg/g and electrosorption efficiency of 96.5 %. Besides, the energy consumption was as low as 0.002 kWh/m3. Furthermore, the remarkable selectivity for F- even in mixed ions systems was confirmed, and the actual fluorine-containing groundwater could be effectively treated to meet the WHO drinking water standard. With the help of characterization techniques and theoretical calculation, the detailed fluorine removal mechanisms were obtained, including physical adsorption, electrostatic attraction, capacitive adsorption and ligand exchange. This work not only proposed new insights into the efficient and selective fluorine removal, but also promoted the development of targeted electrodes for practical application in treating fluorine pollution in groundwater.

Porous carbonaceous materials derived from agroforestry biowaste are of great interest for environmental remediation because of not only their unique composition and structure, which provide a highly accessible surface area and consequently many exposed active sites but also their stable recycling performance. However, finding a green and low-cost way to prepare porous biochars with the desired composition and structure has been challenging. Herein, we report a green and simple carbonization method for the low-cost synthesis of micro-mesoporous biochars (MMBs) using biowaste and eggshell. Without chemical activation agents, the specific surface area and pore volume of the MMBs reached 1949 m(2) g(-1) and 1.21 cm(3) g(-1), respectively. Graphite-like structures and abundant O-containing surface functional groups formed. A high carbonization temperature, >= 800 degrees C, was crucial for eggshell decomposition and played a role in pore opening. Pore filling led to excellent sorption removal of pollutants. The sorption amount for diethyl phthalate reached 456 mg g(-1). Hydrogen bonding and pi-pi stacking, as well as mass transfer, controlled the sorption rate. This novel synthetic method provides a simple way to prepare carbonaceous materials with advantageous properties for a variety of potential environmental and energy applications, such as wastewater treatment, gas capture, and energy storage and conversion.

Due to its high nutrient utilization efficiency, liquid organic fertilizer has become a research hotspot in the field of agricultural planting. Artificial humic acids, which are near-nature products, can be deemed as a green liquid organic fertilizer, but few studies have been reported, which has limited their further application. In this study, artificial humic acids were derived from municipal sludge, and their effect on rice growth, soil fertility, and dissolved organic matter was investigated using multi-chamber root box experiments. The shoot and root biomass of rice can be significantly enhanced by artificial humic acids, and the heavy metal concentration in rice was within safe limits. Artificial humic acids can limit the decrease in soil pH, especially in the far-rhizosphere zone, and improve the distribution of nutrients in the rhizosphere, near-rhizosphere, and far-rhizosphere zones. The use of artificial humic acids led to a significant decrease in soil electrical conductivity. The dissolved organic carbon content in the root zone was significantly increased, and the fluorescence intensity of dissolved organic matter in the rhizosphere was significantly increased. The proportion of specific components of dissolved organic matter was just slightly changed in the rhizosphere and near-rhizosphere zones. Artificial humic acids promoted the humification of dissolved organic matter in the near-rhizosphere and far-rhizosphere zones. The findings indicate that the environmental impact of artificial humic acids is significantly different from conventional chemical fertilizers, and they show huge potential in the agriculture field.

Low-cost multifunctional sorbents are urgently needed, especially for the treatment of emerging pollutants that are widely distributed in various water environments. This work transformed an aquatic invasive plant, Pistia stratotes, into magnetic porous biochars (P-MPBs) based on a proposed strategy involving sequential carbonization to increase porosity and subsequent coprecipitation with ferric salts. Both the porous structure (specific surface area of up to 996.86 m2/g) and high Fe3O4 loading (saturation magnetization of up to 23.48 emu/g) were maintained. A typical plasticizer, diethyl phthalate (DEP), was selected as a model emerging organic pollutant, and the sorption quantity of the P-MPBs reached 490.04 mg g−1, which is much higher than that of many reported sorbents, especially magnetic sorbents. P-MPBs can be reused multiple times due to their excellent separation characteristics and stable structure. On the basis of kinetics and isotherm analysis, multilayer sorption, including pore filling, hydrogen bonding, π–π stacking, and partitioning, was the main DEP sorption process for the P-MPBs. Our study suggested that the proposed method could be promising and inspiring for the transformation of biowaste into excellent magnetic porous biochar that is recyclable and highly efficient at removing pollutants in water.

Manure biogas residue has attracted increasing attention in waste recycling but faces substantial challenges because of its low carbon content, high ash content, and high heavy metal content. A novel sequential carbonization approach was proposed for recycling biogas residue; this approach consisted of pre-pyrolysis, activation with Ca(OH)(2), and then activation with KOH. Pig manure-derived biogas residue was upcycled into engineered biochar (EB) with a high yield (26 %) and showed excellent performance in removing a typical plasticizer, diethyl phthalate (DEP). The proportion of carbon content greatly increased from 18 % (biogas residue) to 67 % (EB); however, the ash content decreased from 50 % (biogas residue) to 24 % (EB). The concentration of heavy metals decreased, and Zn had the largest decrease from 713 mg kg(-1) to 61 mg kg(-1) (p < 0.001). The sorption of DEP onto EB was rapid and reached equilibrium within 20 h. The developed specific surface area of EB was 1247 m(2)/g and provided abundant sorption sites for DEP; additionally, the sorption quantity reached 309 mg/g. The sorption capacity was dominated by surface adsorption. The oxygen-containing functional groups, graphene structure, porous structure, and hydrophobicity of EB contributed to the pore filling, hydrogen bonding, pi-pi stacking, and partitioning processes. Furthermore, the EB showed excellent practical application potential and great cycling stability. A sequential carbonization strategy was proposed to upcycle manure biogas residue into the EB for DEP removal; moreover, this strategy can aid in the attainment of environmental sustainability, including sustainable waste management and environmental pollution mitigation.

Highly developed porous materials are urgently needed for the efficient remediation of contaminated environments. However, their preparation methods are extremely limited, and new production processes have always been a research focus. In this study, a green and efficient sequential carbonization method was proposed to prepare excellent porous biochar from bamboo waste; the sequential steps were hydrothermal carbonization, potassium/calcium formate-assisted prepyrolysis, and urea-assisted postpyrolysis. The specific surface area reached 3921 m2/g, which is much greater than that of reported porous materials, and the pore volume reached 1.87 cm3 g-1. Moreover, the nitrogen content was as high as 2.04 %. The developed nitrogen-doped porous biochars (NPBs) were applied to the sorption of a typical plasticizer, diethyl phthalate, from water. The surface sorption quantity dominated the entire sorption capacity. The maximum sorption amount was 823.46 mg g-1. Pore filling, partitioning, hydrogen bonding and 7C-7C stacking are possible sorption mechanisms. In addition, the stable properties of NPBs have great potential for recycling. This work has developed a high-value, green method to prepare excellent porous materials with great promise for the sorption of pollutants and could be further applied in the fields of catalysis, energy storage, and filtration.

Efficient sorbents that have high sorption capacity and suitable separability are promising and are urgently needed to remove diverse contaminants from water environments. In this study, nitrogen-doped magnetic porous biochars (NMPBs) were synthesized from marine algae by a three-step process consisting of prepyrolysis, copyrolysis and coprecipitation. For NMPBs, the surface area was up to 1531 m2/g, the magnetization strength was up to 31 emu/g, and the surface nitrogen content was up to 3 %. The NMPBs showed the expected sorption capability for sulfamethoxazole, with the removal quantity reaching 502 mg g-1 based on the sorption isotherm model. NMPBs also showed excellent separability and reusability, and the removal rate remained at 87 % after seven cycles. Partitioning and adsorption, including pore filling, hydrogen bonding, pi-pi stacking, partitioning and electrostatic interactions, were the sorption processes in removing sulfamethoxazole. In this work, marine algae were converted into an engineered biochar that is promising for environmental remediation.

This study examines the fluorescence characteristics of dissolved organic matter (DOM) in soils from different periods of rice–crayfish integrated systems (RCISs) in China. Utilizing three-dimensional excitation–emission matrix (3D-EEM) fluorescence spectroscopy, the study investigated the hydrophobicity, molecular weight distributions, and fluorescence properties of DOM in 2-, 5-, and 7-year RCIS operations, with rice monoculture (RM) serving as a control. The findings indicate that in the initial 2 years of an RCIS, factors such as rice straw deposition, root exudates, and crayfish excretions increase dissolved organic carbon (DOC) release and alter DOM composition, increasing the humic acid content in the soil. As the system matures at 5 years, improvements in soil structure and microbial activity lead to the breakdown of high-molecular-weight humic substances and a rise in small-molecular-weight amino acids. By the 7-year mark, as the aquatic ecosystem stabilizes, there is an increase in humic substances and the humification index in the soil DOM. These variations in DOM properties are essential for understanding the effects of integrated farming systems on soil quality and sustainability.

Low-cost and green preparation of efficient sorbents is critical to the removal of organic contaminants during water treatment. In this study, the co-pyrolysis of macroalgae and oyster shell was designed to synthesize nitrogen-doped porous biochars for sorption removal of atrazine from water. Oyster shell played a significant role in opening pores in macroalgae-derived biochars, resulting in the surface area of the macroalgae (Enteromorpha prolifera and Ulva lactuca) and oyster shell co-pyrolyzed carbonaceous as high as 1501.80 m2 g−1 and 1067.18 m2 g−1, the pore volume reached 1.04 cm3 g−1 and 0.93 cm3 g−1, and O/C decreased to 0.09 and 0.08, respectively. The sorption capacity of atrazine to nitrogen-doped porous biochars (the Enteromorpha prolifera, Ulva lactuca and oyster shell co-pyrolyzed carbonaceous) reached 312.06 mg g−1 and 340.52 mg g−1. Pore-filling, hydrogen bonding, π-π or p-π stacking and electrostatic interaction dominated the multilayer sorption process. Moreover, the nitrogen-doped porous biochars showed great performance in cyclic reusability, and the Enteromorpha prolifera, Ulva lactuca and oyster shell co-pyrolyzed carbonaceous sorption capacity still reached 246.13 mg g−1 and 255.97 mg g−1, respectively. Thus, this study suggested that it is feasible and efficient to remove organic contaminants with the nitrogen-doped porous biochars co-pyrolyzed from macroalgae and oyster shell, providing a potential green resource utilization of aquatic wastes for environmental remediation.

The utilization of urban waste for land management plays a crucial role in reshaping material flows between human activities and the environment. Sewage sludge alkaline thermal hydrolysis (ATH) produces sludge-derived plant biostimulants (SPB), which have garnered attention due to the presence of indole-3-acetic acid. However, there remains a gap in understanding SPB's molecular-level effects and its comprehensive impact on crops throughout their growth cycle. In this study, non-targeted and targeted metabolomic approaches are employed to analyze 51 plant hormones and 1,177 metabolites, revealing novel insights. The findings demonstrate that low concentrations of SPB exerted multiple beneficial effects on rice roots, leaves, and the root-soil system, facilitating rapid cell division and enhancing antioxidant defense mechanisms. These results provide a vital foundation for understanding ATH metabolic pathways and advocating for widespread SPB application, offering significant implications for sustainable land management.

Biochar and hydrochar have garnered widespread attention owing to their excellent performance in environmental remediation, carbon sequestration, and resource utilization from biowaste. Studies on the release potential of dissolved organic matter (DOM) have been limited, and the distinction between biochar and hydrochar remains unclear. In this study, pine sawdust was utilized as a model precursor with the aim of comparing the release quantity, components, and properties of DOM from biochar (BDOM) and hydrochar (HDOM) under various simulated conditions. The amount of DOM released by hydrochar (38.20-190.49 g/kg) was significantly greater than that released by biochar (0.57-11.96 g/kg), and more DOM was released at higher temperatures and pH values. BDOM consists of three categories of components, namely, humic-like, protein-like, and benzoic acid-like and tyrosine-like substances compounds, whereas HDOM consists of four categories of components, namely, two categories of humic-like compounds and two categories of protein-like compounds. By using ESI-FT-ICR-MS technology, 8586 compounds in BDOM and 6428 compounds in HDOM were identified. A total of 4665 unique compounds were found in BDOM, 1416 unique compounds were found in HDOM under alkaline release conditions, and HDOM contained more unique compounds than those found in other environments. CRAM/lignin-like compounds made up the majority of the released DOM and reached 31.01-65.35 % for BDOM and 54.79-73.05 % for HDOM. These findings revealed significant differences in the release potential of DOM from biochar and hydrochar, and further behavior research is needed to guide future applications of char materials in the environment and agriculture fields.

Excellent biochar properties are crucial for sorption performance, and a developed pore structure is especially important. Herein, novel porous carbon/porous biochar (PC/PB) composites, in which the porous biochar and porous carbon were prepared at the same time, were synthesized via a green method from algal biomass with the help of the self-activation of citrate for the first time, and the composites were evaluated for the sorption of sulfamethoxazole (SMX). Many micro/meso/macropores were introduced into the PC/PB composites, which showed high specific surface areas (up to 1415 m2/g) and pore volumes (up to 1.08 cm3 g-1). The PC/PB composites displayed excellent SMX sorption capacities, which reached 844 mg g-1. Pore filling played a crucial role in determining the sorption capacity, and hydrogen bonding, electrostatic interactions and 7C-7C stacking controlled the sorption rate. This study provides an improved method for preparation of porous biochar.