Regulation mechanisms of biochar-derived endogenous substances on heavy metal mobility in the soil-crop system: A critical review.

The utilization of biochar (BC) for the remediation of heavy metals (HMs) in contaminated soils has attracted considerable global interest. This review synthesizes advancements in the formation, composition, and fraction distribution of endogenous substances in BC, as well as their roles in regulating both cationic and anionic HMs in soils over the past decade (up to 2025). The physicochemical and structural properties of BC are determined by feedstock selection and pyrolysis temperature, which regulate the composition, concentration, and fractionation of its constituents.

Application of green waste polyphenols in natural antimicrobial materials for the environmental fields: A review.

In recent years, green waste polyphenols (GWPs) have attracted global attention due to their abundant renewable resources and excellent antibacterial properties. We analyzed the research progress on the antimicrobial properties of natural polyphenol composites (including polyphenol-metal nanoparticles, polyphenol nanofiber membranes, polyphenol-polymer membranes, and polyphenol hydrogels) in environmental applications. The waste sources of polyphenols and the latest extraction technologies were systematically summarized, and a universal hydrodynamic cavitation-integrated membrane technology combined with polyphenol extraction and purification process was initially constructed.

Fertilization of potentially toxic element-contaminated soils remediated with reusable biochar pellets using rice straw, pig manure and their derived biochar.

Potentially toxic elements (PTEs) are widespread pollutants in agricultural fields, presenting significant challenges to the maintenance of soil ecological functions while simultaneously reducing their concentrations. This study detailed the development of a high-strength reusable silicate magnetic composite biochar sphere (SMBCS) characterized by superior magnetic and adsorption properties, synthesized from natural minerals and biochar. The application of SMBCS over three consecutive remediation cycles led to reductions in cadmium (Cd), lead (Pb), and arsenic (As) concentrations in soil by 28.

Biochar application for the remediation of soil contaminated with potentially toxic elements: Current situation and challenges.

Recently, biochar has garnered extensive attention in the remediation of soils contaminated with potentially toxic elements (PTEs) owing to its exceptional adsorption properties and straightforward operation. Most researchers have primarily concentrated on the effects, mechanisms, impact factors, and risks of biochar in remediation of PTEs. However, concerns about the long-term safety and impact of biochar have restricted its application.

New Straw Coating Material for Improving the Slow-Release Performance of Fertilizers.

In this work, we extracted cellulose from agricultural waste and produced a new straw coating material (ethyl cellulose, EC) through a series of modification operations. The slow-release properties of ethyl cellulose-coated urea (EU) and its absorption and utilization by plants were evaluated. The surface of EU can form a smooth and fine film, and the initial nutrient release rate is only 37.

Adsorption effect and the removal mechanism of silicate composite biochar particles on cadmium in soil.

Ordinary biochar has the disadvantages of low strength and fragility, and it is difficult to be separated in heavy metal contaminated soil after the remediation process. In order to realize the recovery and reuse of biochar, we prepared silicate composite biochar (SCB) and the magnetic silicate composite biochar (MSCB) with consistent particle size and high hardness. As well as the passivation effect and mechanism of the material on cadmium in soil was also investigated.

Characteristics and preparation of oil-coated fertilizers: A review.

As the slow-release fertilizer, oil-coated fertilizer can not only slow down the nutrients loss, but also have outstanding advantages in controlling the nutrients release. Based on a large number of literature, this paper systematically investigated the composition, classification, properties and preparation of oil-coated fertilizers, summarizes the challenges faced by the oil-coated fertilizers and offers a few suggestions for the future research. Through literature research, some important conclusions were found: (1) Oil-coated fertilizers are generally composed of core fertilizers and coated oil layers, and some have active interlayers.

Effects of ecological protection and restoration on phytoplankton diversity in impounded lakes along the eastern route of China's South-to-North Water Diversion Project.

Traditional lake phytoplankton diversity studies do not take into account the impact of ecological protection and restoration project policies. Here, a difference-in-differences (DID) model, which is commonly used to analyze the relative importance of economic factors, was used to evaluate the impact of such policies on phytoplankton diversity in lakes. Dongping Lake was used as the experimental group, and the upstream Nansi Lake was used as the control group.

Modeling water quantity and quality for a typical agricultural plain basin of northern China by a coupled model.

Water crisis across the globe has placed high pressure on social development due to the need to balance the water consumption between sustainable economy and functioning ecosystem. Integrated process-based modeling has been reported as an effective tool to better understand the complex mechanisms of water issues on a basin scale. Considering that it is still relatively difficult to simulate the water quantity-quality processes simultaneously, this study proposed an integrated modeling framework by coupling a hydrological model with a water quality model.

Dynamic landscapes and the driving forces in the Yellow River Delta wetland region in the past four decades.

Wetlands provide a broad range of ecosystem services, such as flood control, groundwater replenishment, and water purification. These services are particularly important in the Yellow River Delta, one of four estuarine deltas in China. The aim of this study was to examine the patterns and drivers forces of wetland landscape in the Yellow River Delta.

Mechanism of cadmium removal from soil by silicate composite biochar and its recycling.

Biochar added to the soil is generally difficult to separate. In order to solve the problem of separating biochar from soil, this paper applies a hydraulic silicate gel material to the preparation of biochar. Non-magnetic silicate bonded biochar (SBC) and magnetic silicate bonded biochar (MSBC) with hydraulic properties were prepared.

Effect of returning biochar from different pyrolysis temperatures and atmospheres on the growth of leaf-used lettuce.

The aim of this study is to evaluate the effects of biochar on the plant's growth. A pot experiment was carried out in our study. Rice straw-derived biochar were charred at two heating temperatures (400 °C/800 °C) and two oxygen-limited atmospheres (CO/N), respectively.

Contributions and mechanisms of components in modified biochar to adsorb cadmium in aqueous solution.

Recently, researchers have carried out a large number of studies on the adsorption of heavy metals by modified biochar, but there have been fewer explorations of the contributions and mechanisms of components in biochar composites on heavy metals adsorption. In this paper, the biochar was modified by Fe/Fe and NaOH, and a further analysis of the adsorption of cadmium on the new biochar was conducted. It was found that (1) the adsorption capacity for cadmium of the modified biochar (M85) was 406.

Preparation of high porosity biochar materials by template method: a review.

Biochar plays an important role in soil improvement, pollutant removal, and nitrogen reduction. The excellent adsorption performance of biochar is closely related to its pore structure. Therefore, this paper combines a large amount of literatures to investigate the principle and method of preparing carbon materials by using the template method, and the idea of preparing high porosity biochar by template method was proposed.

Effects of pyrolysis conditions on migration and distribution of biochar nitrogen in the soil-plant-atmosphere system.

The use of biochar to amend soil has been gaining increasing attention in recent years. In this study, the N tracer technique was used together with elemental analysis-stable isotope ratio analysis and gas isotope mass spectrometry to characterise biochar, soil, plant, and gas samples in order to explore the nitrogen transport mechanisms in the biochar-soil-plant-atmosphere system during the process of returning biochar to the soil (RBS). The results showed that the nitrogen retention rate of biochar was negatively correlated with the pyrolysis temperature during the preparation process, but was less affected by the pyrolysis atmosphere.

Preparation of biochar with high absorbability and its nutrient adsorption-desorption behaviour.

To study the formation of biochar with high absorbability, experiments were carried out at different carbonization temperature (300, 400, 600, and 800 °C) and under different carbonization atmosphere (activating gases (steam and CO) and inert gas (N)) to prepare biochar. In this paper, the effects of the carbonization atmosphere on the biochar pore structure were studied, and the influence of the biochar pore structure on the adsorption-desorption behaviour of nutrients (NH-N, NO-N, P, and K) was investigated. Experimental results: (1) The activating gases (steam and CO) can catalytically crack activated carbon atoms and tar blocking the biochar pores at high temperatures (T > 600 °C), and the activating gas promotes the formation of microporous biochar (d < 2 nm).

Mechanism of negative surface charge formation on biochar and its effect on the fixation of soil Cd.

The studies of the mechanism of Cd fixation by biochar have mainly focused on the pore size, pH, and oxygen-containing functional groups, and few researches have paid close attention to the effect of the negative charge in biochar surface. In this paper, biochar was produced in the CO atmosphere at different pyrolysis temperatures, and the influence of the pyrolysis temperature on biochar surface charge were explored. The cause of the negative charge on the biochar surface has been analysed, and the optimal preparing temperature for the biochar with the best effect of cadmium immobilization from soil has been found.

Vertical variations of soil water and its controlling factors based on the structural equation model in a semi-arid grassland.

Soil water content (SWC) of a vertical profile plays an important role in the soil-plant-atmosphere continuum system through eco-hydrological process, which was controlled by multiple factors. Previous studies ignored soil water from a systematic perspective because of the lack of suitable methods to deal with interrelated factors. We developed a meta-model based on structural equation model (SEM) to identify the factors contributing to soil water, and the interactions among these factors, in a semi-arid grassland system.

Effect mechanism of biochar's zeta potential on farmland soil's cadmium immobilization.

In situ passivation of heavy metals by biochar mainly focuses on the effect of biochar's pH, surface oxygen-containing functional groups (OCFGs), and ash content. In this paper, starting with the measurement of biochar's electrical properties under different pyrolysis atmospheres and temperatures, the changes in the zeta potential of biochar and the consequent effects on cadmium immobilization in soil are studied. The results show that the zeta potential of biochar from the pyrolysis of high temperature (800 °C) is higher than that of biochar at low temperatures, so its electronegativity is weaker than that of biochar at low temperatures, but the protective effect on wheat is stronger than that of biochar obtained at low temperatures.

Application of the N tracer method to study the effect of pyrolysis temperature and atmosphere on the distribution of biochar nitrogen in the biomass-biochar-plant system.

Biochar nitrogen is key to improving soil fertility, but the distribution of biochar nitrogen in the biomass-biochar-plant system is still unclear. To provide clarity, the N tracer method was utilised to study the distribution of biochar nitrogen in the biochar both before and after its addition to the soil. The results can be summarised as follows.

Study of the mechanism of remediation of Cd-contaminated soil by novel biochars.

This article used novel non-magnetized and magnetized biochars prepared under a CO atmosphere returned to Cd-contaminated soil and compared these to the effects of conventional biochars prepared under a N atmosphere with regard to Cd-contaminated soil remediation. A pot experiment with lettuce (Lactuca sativa) was conducted to investigate the relative soil remediation effects of these biochars. The soil used for the pot experiment was spiked with 20 mg kg Cd and amended with 5% of a biochar before sowing.

Mechanistic study of the influence of pyrolysis conditions on potassium speciation in biochar "preparation-application" process.

Biochar samples produced from rice straw by pyrolysis at different temperatures (400°C and 800°C) and under different atmospheres (N and CO) were applied to lettuce growth in a 'preparation-application' system. The conversion of potassium in the prepared biochar and the effect of the temperature used for pyrolysis on the bioavailability of potassium in the biochar were investigated. Root samples from lettuce plants grown with and without application of biochar were assayed by X-ray photoelectron spectroscopy (XPS).

Leaching characteristics of fly ash from Chinese medical waste incineration.

Many of the characteristics of typical medical waste ash can be found by using ash leaching experiments. The present study investigated the characteristics of fly ash derived from incineration of medical waste in China. The particle diameter of the fly ash was in the range 154-900 μm.

[Leaching and stabilization of heavy metal in the fly ash of medical wastes].

Through the experiments of leaching and melting on the fly ash of medical wastes, the influence of leaching time, L/S, pH and grain size on the leaching characteristics of heavy metal and the effect of melting on the stabilization of fly ash are studied. Results show that, following the leaching time extending, the leaching concentrations of heavy metals and lixiviate toxicity of heavy metals increase in the fly ash. When the ratio of liquid and solid add, the leaching concentrations of heavy metals obviously become big, and the Cd's leaching concentration is the biggest, when the ratio of liquid and solid is 90, the Cd' s leaching ratio exceed the percent of 70.