Effects of Municipal Sewage Sludge Application on Soil and Purple Moor-grass (Molinia caerulea) Contamination by Metals in a Maritime Pine Forest

Granular bentonite has been assessed regarding its capacity to remove Hg(II), Cd(II) and Pb(II) from aqueous solutions. Sorption capacities, kinetics and the dependence of the sorption process on pH were determined. Fractional power, pseudo-first-order, pseudo-second-order and intra-particle diffusion equations were used to model the kinetics of metal adsorption. The pseudo-second-order model showed the best fit to experimental data. Different two-parameter sorption isotherm models (Langmuir, Freundlich, Temkin and Dubinin?CRadushkevich) were used to fit the equilibrium data. Freundlich's isotherm model gave the best fit to experimental data. The selectivity of granular bentonite towards these metals is Pb(II)?>?Cd(II)?>?Hg(II). The adsorption capacities of granular bentonite towards the metals expressed in milligramme metal per gramme granular bentonite are 19.45, 13.05 and 1.7 for Pb(II), Cd(II) and Hg(II), respectively (for an initial concentration of 100 mg metal/L).     

Evaluation of Green Waste and Popular Twigs Biochar Produced at Low and High Pyrolytic Temperature for Efficient Removal of Metals from Water

Biomass-derived biochar is considered as a promising heavy metal adsorbent, due to its favorable physicochemical properties, from aqueous solution as compared with other adsorbents. However, there is a limited number of studies on the effects of biochar produced from different feedstocks and pyrolytic temperatures on metal removal from metal-contaminated water. So in this study, the removal of the most prevalent heavy metals [(lead (Pb(II)), cadmium (Cd), and chromium (Cr)] by green waste biochar (GWB) and popular twigs biochar (PTB), produced at different pyrolytic temperatures, i.e., low 350 and high 650 °C, has been investigated, following the determination of physical and chemical properties of biochar. The efficiency of heavy metals removal of biochar was studied at different concentrations of heavy metals (10 and 100 μg mL^?1), biochar types and treatment duration (3, 6, 9, and 12 h) at isothermic condition of aqueous solution. Results revealed that both feedstock type and pyrolytic temperature to produce biochar significantly affected its metal sorption capacity. The maximum sorption capacities of all three metals, i.e., Pb (II), Cd, and Cr were determined in the GWB produced at low pyrolytic temperature 350 °C after 9 h of treatment duration at both high and low metal concentrations. This highest sorption capacity of all metals by low pyrolytic temperature produced GWB was due to its better physicochemical properties especially high surface area, cation exchange capacity, and oxygen-containing functional groups as compared with woody feedstock based high pyrolytic temperature produced PTB. Conclusively, low pyrolytic temperature produced GWB was evaluated as a potential adsorbent to efficiently reduced heavy metal concentration in metal-contaminated water.     

三种改性小麦秸秆生物炭表征及其对Cu2+的吸附性能

为研究改性生物炭在水溶液中对Cu2+的吸附性能,利用硅酸钠溶液、氯化镁溶液、过氧化氢溶液制备了3种不同改性小麦秸秆生物炭,通过使用扫描电镜-X射线能量色散光谱（scanning electron microscopy combined with energy dispersive X-ray spectroscopy,SEM-EDS）和傅里叶红外光谱（Fourier infrared spectroscopy,FTIR）等技术对改性前后的生物炭进行表征分析,探究其表面形貌、官能团等性质变化。硅酸钠改性生物炭（sodium silicate modified biochar,SBC）的比表面积与孔容最大,分别为43.69 m2/g、5.30 cm3/g,比未改性生物炭（biochar,BC）（6.02 m2/g、1.40 cm3/g）分别增加了6.25、2.79倍。由SEM-EDS结果表明,改性生物炭均出现C元素质量分数下降、O元素质量分数增加的现象,其中,SBC的C元素和O元素质量分数变化最大,且SBC和氯化镁改性生物炭（magnesium chloride modified biochar,MBC）上负载了大量含Si和Mg的颗粒。FTIR结果表明,改性处理均能增强官能团的峰值,硅酸钠改性增强程度最大。另外,过氧化氢改性生物炭（hydrogen peroxide modified biochar,HBC）、BC、MBC 和SBC对Cu2+的吸附动力学过程更符合准一级动力学模型,BC、MBC、SBC对Cu2+的等温吸附过程更符合Langmuir模型,HBC对Cu2+的等温吸附过程更符合Freundlich模型。分析吸附模型参数可知,改性生物炭MBC、SBC和HBC中,SBC对Cu2+的吸附能力更强,其理论吸附量可以达到230.20 mg/g,该结果可为改性生物炭对Cu2+污染水体的治理提供理论依据。     

Potentially hazardous element accumulation in rice tissues and their availability in soil systems after biochar amendments

Purpose

Biochar has shown to be a great product to control the bioavailability of potentially hazardous elements (PHE) in contaminated soils. Despite the advantages associated with the application of biochar in agricultural soils, relatively few studies have focused on the effects of biochar amendments on soil chemical properties, accumulation of arsenic, cadmium, zinc, and lead in rice tissues, and their availability in soil systems.

Materials and methods

The field experiment was conducted at the paddy soils in Hunan Province, China. The soil texture was sandy clay loam. Wheat-derived biochar was applied once to the experimental plots at the rates of 0, 10, 20, 30 and 40 t ha^?1, and referenced as A0, A10, A20, A30, and A40, respectively. For PHE determination, soil samples and plant samples were digested with a mixed solution of HCl:HNO₃ (4:1, V:V) and HCl:HClO₄ (4:1, V:V), respectively, and the arsenic, cadmium, zinc, and lead in the digest solution were measured by ICP-MS (Thermo Fisher Scientific, USA). The soil available fraction of PHE (arsenic, cadmium, zinc, and lead) was extracted by diethylenetriamine pentaacetic acid (DTPA) and measured by inductively ICP-MS.

Results and discussion

Biochar amendment increased chemical properties of soil organic matter, pH, electrical conductivity, cation exchange capacity, nitrate nitrogen, and available phosphorus. Soil DTPA extractable arsenic, cadmium, zinc, and lead concentrations were significantly reduced. Arsenic, cadmium, zinc, and lead in rice shoots, and arsenic, cadmium, and zinc in roots significantly decreased after amendment. Concentrations in rice tissues positively and negatively correlated with the soil available fraction of PHE and soil chemical properties, respectively. Soil electrical conductivity negatively correlated with the soil available fraction of PHE. Concentrations of arsenic, zinc, cadmium, and lead in rice roots declined relative to increases of cation exchange capacity (arsenic, zinc), available phosphorus (cadmium), and nitric nitrogen (lead) content. Similar relationships were observed between cation exchange capacity and PHE in shoots.

Conclusions

Biochar creates avoidance of PHE through regulating chemical properties through biochar sorption capacity. Cation exchange capacity, available phosphorus, and nitric nitrogen were the principle factors affecting roots uptake of arsenic, zinc, cadmium, and lead. Biochar soluble salts could decline availability of metals/metalloids in soils through precipitation. Wheat-derived biochar application is an alternative safe product to immobilize PHE in rice paddy soils by restricting the risk of PHE.

     

花生壳生物炭对土壤吸附邻苯二甲酸二甲酯的影响

采用限氧升温法在不同的炭化温度和时间下制备4种花生壳生物炭,考察其对土壤吸附邻苯二甲酸二甲酯(Dimethyl phthalate,DMP)的影响。结果表明,添加生物炭能显著提高土壤对DMP的吸附能力。Langmuir模型和Freundlich模型均能较好的拟合添加生物炭土壤对DMP的吸附,相关系数分别介于0.90~1.00和0.95~0.99之间。随着生物炭添加量的增加,土壤对DMP的吸附能力明显增强且非线性特征更加突出;在生物炭高添加量条件下,炭化温度高且炭化时间长的生物炭对土壤吸附能力的增强作用更为显著。在Ce=0.001 Sw和Ce=0.01 Sw条件下,生物炭对土壤吸附DMP的贡献率分别介于80.80%~98.58%和67.30%~96.37%之间,表明生物炭对土壤吸附DMP发挥着主导作用。     

菲和Cu^2＋在黑垆土上的吸附及其交互影响

采用批平衡法,研究了菲和Cu2＋在黑垆土上的吸附及其交互影响。结果表明,菲和Cu2＋在黑垆土上的吸附动力学曲线较好符合一级动力学方程,菲在黑垆土上的吸附主要通过分配作用,其吸附等温曲线符合线性Henry方程,Cu2＋的存在抑制菲在黑垆土上的吸附;而Cu2＋在黑垆土上的吸附主要通过表面吸附和专性吸附作用,其吸附等温曲线符合Freundlich方程,菲的存在促进了Cu2＋的吸附;对菲和Cu2＋来说,pH均是影响黑垆土吸附的主要因素,黑垆土对Cu2＋的吸附量随着土壤溶液pH值的增加而增加,而对菲的吸附量随着pH增加而降低。     

猪粪制备的生物炭对西维因的吸附与催化水解作用

以猪粪为原料,在不同温度下制备生物炭,并对其进行除灰处理,研究了不同处理温度和灰分含量的生物炭与西维因的相互作用。猪粪制备的生物炭含有无机矿物、不定型有机质和结晶态芳香碳,且随处理温度升高,灰分含量增加,BET比表面积增加。生物炭对西维因的吸附表现为非线性,等温线符合Freundlich方程,且随生物炭制备温度的升高,非线性增强。生物炭除灰后,吸附作用大大增强,表明有机碳与无机成分复合造成其一部分吸附点位的损失。生物炭对西维因的吸附由亲脂性分配与特殊作用力构成,随着生物炭不同以及西维因浓度的变化,吸附机制发生变化。生物炭可提高溶液pH,pH随生物炭添加量和处理温度而升高,生物炭含有的矿物对西维因水解具有催化作用,其水解速率及程度与生物炭灰分含量呈正相关。     

天然磁铁矿和商用Fe3O4修复Hg(II)污染地下水的模拟研究

目前汞污染地下水修复面临很大的技术和成本挑战,亟需发展修复效果好、经济效益性高的汞污染地下水修复技术和修复材料。通过批量实验和光谱分析探究了天然磁铁矿和商用Fe_3O_4对Hg(Ⅱ)的去除效率和去除机制,并分析了两种材料对模拟地下水中Hg(Ⅱ)的吸附和脱附行为。结果表明,天然磁铁矿和商用Fe_3O_4对Hg(Ⅱ)的去除受pH、Hg(Ⅱ)初始浓度、Cl-等因素的影响;二者对Hg(Ⅱ)的去除均符合准二级动力学模型和Freundlich模型;天然磁铁矿对Hg(Ⅱ)的去除机制主要是羟基络合与物理吸附,而商用Fe_3O_4对Hg(Ⅱ)的去除主要是化学还原与物理吸附。二者对模拟地下水中Hg(Ⅱ)的去除率分别达90%和95%,具有修复Hg(Ⅱ)污染地下水的应用潜力。     

Removal of Mercury Ions from Mixed Aqueous Metal Solutions by Natural and Modified Zeolitic Minerals

Research works on the removal of mercury from water by zeolitic mineralshow that small quantities of this element are sorbed. In this work the mercury sorption from aqueous solutions in the presence and absence of Cu(II), Ni(II) and Zn(II) onto a Mexican zeolitic mineral unmodified and modified with cysteamine hydrochloride or cystamine dihydrochloride was investigated in acidic pH. The zeolitic minerals were characterized by thermogravimetric analysis, scanning electron microscopy, X-ray diffraction and FTIR. The sorption kinetics behavior and the retention isotherms for mercury were determined in the natural and treated zeolitic mineral samples. It was found that the amounts of sulfur on the modified zeolitic minerals were 0.375 (cysteamine hydrochloride) and 0.475 (cystamine dihydrochloride) mmol g^-1, which were not saturated to their total capacities of adsorption for the maximum concentration used (0.310 mM). Under the experimental conditions, the retention of mercury was the highest for the zeolitic minerals treated with the organic compounds, with adsorption capacities ranging from 0.0107 to 0.0509 mmol Hg g^-1.The retention was not affected by the presence of others heavy metals studied in this work as expected.     

Batch Chromium(VI), Cadmium(II) and Lead(II) Removal from Aqueous Solutions by Horticultural Peat

The selectivity and uptake capacity of horticultural peat available in Romania was evaluated with respect to the removal of Cd(II), Cr(VI) and Pb(II) ions from aqueous solution. The kinetics, sorption capacities, selectivity and pH dependence of sorption were determined. The influence of metal concentration in solution is discussed in the terms of Langmuir and Freundlich isotherm and constants. Sorption capacities increased with increasing metal concentration in solution. For solutions containing 300 mg/l of metal, the observed uptake capacities were 20 mg Cd(II)/g peat, 15 mg Cr(VI)/g peat and 30 mg Pb(II)/g peat. The study proved that horticultural peat is a suitable material for the removal of the studied heavy metal ions from aqueous solutions, achieving removal efficiencies higher than 90%, and could be considered as a potential material for treating effluent polluted with Cd(II), Cr(VI) and Pb(II) ions.     

Copper Binding by Activated Biochar Fibres Derived from <Emphasis Type="Italic">Luffa cylindrica</Emphasis>

The adsorption of copper (Cu(II)) from aqueous solutions by activated Luffa cylindrica biochar fibres has been investigated by means of batch equilibrium experiments and FTIR spectroscopy. The effect of various physicochemical parameters, such as pH, initial metal concentration, ionic strength, mass of the adsorbent, contact time and temperature, has been evaluated by means of batch type adsorption experiments. FTIR spectroscopy, as well as acid-base titrations, was used for the characterization of the material and the surface species formed. According to the experimental results even at pH 3, the relative sorption is above 85% and the adsorption capacity of the activated biochar fibres for Cu(II) is q _max = 248 g kg^?1. Moreover, the interaction between the surface carboxylic moieties and Cu(II) results in the formation of very stable inner-sphere complexes (?G ^o = ?11.2 kJ mol^?1 at pH 3 and ?22.4 kJ mol^?1 at pH 5.5).     

Sorption of triazine and organophosphorus pesticides on soil and biochar

Sorption and degradation are the primary processes controlling the efficacy and runoff contamination risk of agrochemicals. Considering the longevity of biochar in agroecosystems, biochar soil amendment must be carefully evaluated on the basis of the target agrochemical and soil types to achieve agricultural (minimum impact on efficacy) and environmental (minimum runoff contamination) benefits. In this study, sorption-desorption isotherms and kinetics of triazine (deisopropylatrazine) and organophosphorus (malathion, parathion, and diazinon) pesticides were first investigated on various soil types ranging from clayey, acidic Puerto Rican forest soil (PR) to heavy metal contaminated small arms range (SAR) soils of sandy and peaty nature. On PR, malathion sorption did not reach equilibrium during the 3 week study. Comparison of solution-phase molar phosphorus and agrochemical concentrations suggested that degradation products of organophosphorus pesticides were bound on soil surfaces. The degree of sorption on different soils showed the following increasing trend: deisopropylatrazine < malathion < diazinon < parathion. While sorption of deisopropylatrazine on SAR soils was not affected by diazinon or malathion, deisopropylatrazine suppressed the sorption of diazinon and malathion. Deisopropylatrazine irreversibly sorbed on biochars, and greater sorption was observed with higher Brunauer-Emmett-Teller surface area of biochar (4.7-2061 mg g(-1)). The results suggested the utility of biochar for remediation of sites where concentrations of highly stable and mobile agrochemicals exceed the water-quality benchmarks.     

Adsorption of Copper(II) Ion from Aqueous Solution Using Biochar Derived from Rambutan (Nepheliumlappaceum) Peel: Feedforward Neural Network Modelling Study

Biochars, derived from rambutan (Nepheliumlappaceum) peel through slow pyrolysis, were characterised and investigated as potential adsorbent for the removal of copper ion, Cu(II) from aqueous solution. Characteristics of five biochars of rambutan peel with different pyrolytic temperatures ranging from 300 to 700 °C (B300, B400, B500, B600, B700) were studied, and adsorption abilities of respective biochars were evaluated. Adsorption experiments were carried out by varying adsorbent dosage (0.2, 0.4, 0.8, 1.0, 2.0, and 4.0 g/L) and initial copper ion, Cu(II) concentrations (50 and 100 mg/L) to determine the optimum pyrolytic temperature of biochar with high adsorption affinity. The adsorption kinetics were best described by the pseudo-second order model for all the tested biochars, while the adsorption equilibrium best fitted by Langmuir isotherm. The overall results showed that biochar derived at 600 °C can be used as an effective adsorbent for removal of Cu(II) from aqueous solutions. Furthermore, feedforward artificial neural network (FFBP) modelling was performed to compare the simulated results with experimental output data of Thermogravimetric analysis (TGA) and atomic absorption spectroscopy (AAS) analysis which were trained using Levenberg-Marquardt (LM) backpropagation algorithm. The FFBP structure for pyrolysis process comprised of TGA temperature as input and biomass final weight as output. The adsorption modelling was simulated using adsorption time, temperature, biochar dosage and initial Cu(II) concentration as input data, while final Cu(II) concentration was used as output data to the network. Finally, modelling structure of 1-9-1 and 4-8-1 gave best performance with regression, R ² value of 0.9999 and 0.9547 for TGA and AAS analysis, respectively.     

Sorption of copper (II) and sulphate to different biochars before and after composting with farmyard manure

Biochar application has been suggested for reducing toxic levels of metals in contaminated soils and enhancing nutrient retention in agro‐ecosystems. We studied sorption of copper (Cu(II)) and sulphate‐sulphur (SO₄‐S) to charcoal, gasification coke and flash‐pyrolysis biochar in order to relate sorption to char properties. Furthermore, we investigated the effect of composting of charcoal and gasification coke on sorptive properties. Langmuir sorption affinity coefficients for Cu(II) for non‐composted biochars increased in the order flash‐pyrolysis char < charcoal < gasification coke. The sorption capacity for Cu(II) of the chars decreased in the order gasification coke (629 mg kg^?1) > flash‐pyrolysis char (196 mg kg^?1) > charcoal (56 mg kg^?1). Composting significantly increased the sorption affinity coefficient approximately by a factor of 5 for charcoal (up to 1.1 l mg^?1) and by a factor of 3–4 for gasification coke (up to 3.2 l mg^?1). Whereas Cu(II) sorption to gasification coke (composted or not) was largely irreversible, sorption to flash‐pyrolysis char and charcoal showed higher reversibility. Relationships between Cu(II) sorption and biochar properties such as cation exchange capacity, specific surface area or aromaticity suggest that sorption was largely determined by complexation with organic matter. Sorption of SO₄‐S was negligible by non‐composted and composted biochars. Composted gasification coke might be suited to reducing toxic Cu(II) concentrations in contaminated soils. Composted charcoal can potentially improve Cu(II) retention in a plant available form in acidic, sandy soils with small organic matter contents. Transient effects of biochars on soil pH can over‐ride the influence of sorption to biochars on concentrations of trace elements in soil solution and their availability to plants.     

秸秆生物质炭吸附溶液中Cu2+ 的影响因素研究

生物质炭在吸附土壤中重金属和有机污染物方面发挥着重要作用,然而关于生物质炭吸附重金属的影响因素研究较少。以小麦和玉米秸秆为原料制备生物质炭,分析了生物质炭和溶液性质对水溶液中Cu2+吸附的影响。结果表明生物质炭可有效吸附Cu2+,且不易解吸。Cu2+吸附量随pH和Cu2+初始浓度的升高而增加;高温炭对Cu2+的吸附随离子强度增强而增大;柠檬酸抑制低温炭对Cu2+的吸附,而腐植酸促进Cu2+吸附;生物质炭灰分对Cu2+吸附无显著影响。     

Biochar Increases Diuron Sorption and Reduces the Potential Contamination of Subsurface Water with Diuron in a Sandy Soil

The herbicide diuron is widely used in agricultural areas in Brazil, whereas it has high potential for subsurface water contamination due to its physicochemical characteristics. Recent studies have demonstrated the potential of biochar as a sorbent and possible pesticide leaching mitigation. The objective of this study was to investigate the long-term effect of biochar application on the kinetics of sorption and desorption of diuron in a Cerrado Haplic Plinthosol. Samples were collected in an experiment conducted in the field in a randomized block design consisting of the combination of two levels of fertilizer application (0 and 300 kg ha^-1 of 5-25-15 formula of NPK fertilizers) and three doses of biochar (0, 16, and 32 Mg ha^-1). The Freundlich isotherm accurately described the sorption of diuron in all treatments. Biochar application increased the sorption and reduced the desorption of diuron. This effect was attributed to the contribution of biochar to total organic carbon (C) and C in the humin fraction and to the increase in the reactivity of the humic acid and humin fractions, which was significantly highly correlated with the sorption coefficient (K_f). A positive correlation between the partition coefficient of organic C and K_f confirmed the importance of the soil organic compartment for the sorption of diuron. The higher diuron sorption and lower diuron desorption capacities of sandy soils after biochar application could reduce the potential risk of diuron leaching and contamination of subsurface water.     

Adsorptive Potential of 2-Mercaptobenzimidazole-Immobilized Organophilic Hydrotalcite for Mercury(II) Ions from Aqueous Phase and Its Kinetic and Equilibrium Profiles

An organophilic calcined hydrotalcite (OHTC) was prepared by treating calcined hydrotalcite (HTC) with sodium dodecylbenzene sulphonate (an anionic surfactant) to achieve a high loading of thiol functionality through the immobilization of 2-mercaptobenzimidazole (MBI) as a chelating agent. The adsorbent (MBI-OHTC) obtained was characterized using XRD, FTIR, SEM, TG/DTG, surface area analysis and potentiometric titration. The adsorption of MBI-OHTC to remove Hg(II) ions from aqueous solutions was studied as a function of pH, contact time, metal ion concentration, ionic strength and adsorbent dose. The optimum pH range for the maximum removal of Hg(II) was 6.0–8.0. The maximum value of Hg(II) adsorption was found to be 11.63 and 21.52 mg g^?1 for an initial concentration of 25 and 50 mg l^?1, respectively at pH 8.0. The equilibrium conditions were achieved within 3 h under the mixing conditions employed. A reversible pseudo-first-order used to test the adsorption kinetics. The adsorption mechanism consisted of external diffusion and intraparticle diffusion and the intraparticle mass transfer diffusion was predominated after 20 min of experiment. Extent of adsorption decreased with increase of ionic strength. The experimental isotherm was analyzed with two parameters (Langmuir and Freundlich) and three parameters (Redlich–Peterson) equations. The isotherm data were best modeled by the Freundlich isotherm equation. Complete removal (≈100%) of Hg(II) from 1.0 l of chlor-alkali industry wastewater containing 9.86 mg Hg(II) ions, was possible with 3 g of the adsorbent dose at pH 8.0. About 95.0% of Hg(II) can be recovered from the spent adsorbent using 0.1 M HCl.     

Manure application followed by biochar application increases plant production regardless of soil dehydrogenase activity

Biochar is obtained by the pyrolysis of biomass, and contains abundant carbon and minerals. Biochar supplementation of soils can greatly improve soil health and quality, but these beneficial effects typically develop slowly over time. Depending on the quality of the biochar and the soil to which it is applied, it may take years before positive effects are apparent. This is because organic substances are slowly sorbed onto the biochar over time, and the biochar eventually becomes part of the sorption complex of the soil. It is therefore advisable to apply biochar together with some organic material. We examined the effect of co-application of different doses of biochar with manure on soil dehydrogenase activity (DHA), soil oxidizable carbon (COX), cumulative soil respiration, soil buffering capacity, the soil exchange reaction (pH/KCl) and the production yield of winter rape seeds. We also determined seed production when artificial granular fertilizers were added to biochar and manure. The results showed that the application of biochar and manure significantly increased grain yield, DHA, the soil exchange reaction and cumulative respiration. Thus, application of biochar with organic material can increase seed yield and some properties of agricultural soils. However, the positive effect of biochar on seed yield was not directly proportional to biochar dose, in that the seed yield was lower for a biochar dose of 45 t/ha than 30 t/ha.     

农田土壤中生物质炭的老化及其对有机污染物吸附-解吸影响的研究进展

生物质炭独特的表面性质、形貌结构及丰富而离散的孔隙系统使其对有机污染物具有良好的持留与吸附作用,可望用于土壤污染控制与修复。在田间条件下,进入土壤的生物质炭自身不稳定组分会发生转化、淋溶,并与土壤发生相互作用出现老化现象,导致生物质炭的化学与物理性质发生显著变化。生物质炭在土壤中的老化过程具有复杂性和多样性,主要包括:生物质炭化学性质的变化,如无机元素的流失、表面官能团组成的变化以及部分矿化反应;生物质炭物理性质的改变,主要是土壤有机质和矿物质对生物质炭的包覆作用造成生物质炭的孔隙特征发生改变。生物质炭在土壤中的老化可能会导致有机污染物的吸附-解吸行为发生改变,且受土壤、生物质炭以及污染物性质的影响较大。本文综述了生物质炭在农田土壤中的老化机理及主要影响因素研究方面的进展,总结了生物质炭在土壤中的老化对有机污染物吸附-解吸行为的影响,提出了尚待解决的相关前沿科学问题。     

Biochar from Different Carbonaceous Waste Materials: Ecotoxicity and Effectiveness in the Sorption of Metal(loid)s

In this study, biochar produced by pyrolysis of urban pruning wood (Bpw) and sewage sludge (Bss) were characterized and investigated as adsorbents for the removal of Cu(II), Pb(II), Zn(II), and As(V) from contaminated solutions. Both types of biochars showed different physical-chemical properties and metal(loid) content. In Bss, Cu, Zn, and Pb concentrations exceeded the upper limit of the common ranges in soils. However, when they were tested for their effect on soil invertebrates, neither of the biochar was expected to exert negative effects as long as the dose applied as an amendment was ≤?4.8 t ha^?1. For an assessment of the effectiveness of biochar in the immobilization of metal(loid)s, three contaminated solutions with acidic pH and different pollutant concentrations were added to both types of biochar. Precipitation as oxy-hydroxides and the formation of complexes with active functional groups of the organic matter were the main mechanisms of metal(loid) fixation by the biochar, with increased precipitation and a rising pH. Both types of biochar were effective at immobilizing Pb and Cu, while Zn showed less effectiveness in this regard and As the least. The high P content of the biochar from sewage sludge favored Pb fixation, presumably forming complexes with phosphates, while competition between phosphate and arsenate ions decreased As adsorption by Fe compounds. The metal(loid)s immobilized by biochar from urban pruning wood were more bioavailable than those fixed by biochar from sewage sludge.