Adsorption removal of roxarsone, arsenite(Ⅲ),and arsenate(Ⅴ) using iron-modified sorghum straw biochar and its kinetics

Arsenic(As)contamination in groundwater is a major problem in many countries,which causes serious health issues.In this paper,a novel method has been developed for the simultaneous removal of ROX and As(Ⅲ/Ⅴ)using the modified sorghum straw biochar(MSSB).The MSSB was characterized by X-ray diffraction,scanning electron microscopy,Fourier Transform Infrared,and Brunauer–Emmet–Teller(BET)surface area.The removal performance of MSSB for ROX,arsenite[As(Ⅲ)],and arsenate(As(Ⅴ))was investigated using batch experiments.At pH of 5,the arsenic concentration of 1.0 mg/L,adsorbent dose of 1.0 g/L,the maximum adsorptioncapacities of ROX,As(Ⅲ),and As(Ⅴ)were 12.4,5.3,and 23.0 mg/g,respectively.The adsorption behaviors were fit well with the Langmuir and the pseudo-second-order rate model.The results showed that MSSB acted as a highly effective adsorbent to simultaneously remove the composite pollution system consisted of ROX and As(Ⅲ/Ⅴ)in aqueous solutions,providing a promising method in environmental restoration applications.

Effect of Rice Straw Biochar on Soil Quality and the Early Growth and Biomass Yield of Two Rice Varieties

Sustainable rice production in Sierra Leone faces serious constraints due to soil acidity, low cation exchange capacity, low nutrient contents accelerated mineralization of soil organic matter and soil loss by erosion (particularly on the uplands). One possible approach to addressing the soil constraints to rice production both on uplands and lowlands of Sierra Leone is the recycling of rice residues through biochar production and application to soils. A pot experiment was conducted to investigate the effects of application of biochar from rice residues on (i) soil physicochemical properties and (ii) the early growth characteristics of two rice varieties, NERICA L19 and ROK3. The experiment was arranged in a completely randomized design (CRD) with two biochar levels (0 and 15 g/kg soil) and two rice varieties in three replications. For the biochar treated soils (+biochar), 75 g rice straw biochar was applied to 5 kg air-dry soil (15 kg biochar/kg soil), mixed thoroughly and placed into perforated black polythene bags. Seeds of two rice varieties, NERICA L19 and ROK3 were planted on the treated and untreated soils for eight weeks. Application of biochar improved available phosphorus, exchangeable cations and cation exchange capacity in biochar treated soils compared to the control soil without biochar. Plant height, tiller number, and dry biomass weight of both rice varieties grown in soils amended with rice straw biochar were significantly higher than those on untreated soils. The most remarkable increase in plant growth characteristics as a result of biochar addition to soil was reflected in the biomass yield and tiller numbers. Dry shoot biomass for ROK3 rice variety varied significantly from a mean of 3.5 g (control) to 26.2 g (+biochar) while tiller numbers significantly varied from 10 (control) to 29.6 (+biochar). Similarly, for NERICA L19 rice variety, dry shoot biomass increased significantly from 4.5 g (control) to 22.7 g (+biochar) while tiller numbers increased significantly from a mean of 12.3 (control) to 30 (+biochar). Thus converting rice residues to biochar and applying to soil holds promise for improving rice production in Sierra Leone.

Effects of Rice Straw and Its Biochar Addition on Soil Labile Carbon and Soil Organic Carbon

Whether the biochar amendment could affect soil organic matter （SOM） turnover and hence soil carbon （C） stock remains poorly understood. Effects of the addition of ^13C-labelled rice straw or its pyrolysed biochar at 250 or 350℃ to a sugarcane soil （Ferrosol） on soil labile C （dissolved organic C, DOC; microbial biomass C, MBC; and mineralizable C, MC） and soil organic C （SOC） were investigated after 112 d of laboratory incubation at 25℃. Four treatments were examined as （1） the control soil without amendment （Soil）; （2） soil plus ^13C-labelled rice straw （Soil＋Straw）; （3） soil plus 250℃ biochar （Soil＋B250） and （4） soil plus 350℃biochar （Soil＋B350）. Compared to un-pyrolysed straw, biochars generally had an increased aryl C, carboxyl C, C and nitrogen concentrations, a decreased O-alkyl C and C：N ratio, but similar alkyl C and δ^13C （1 742- 1 877 %）. Among treatments, significant higher DOC, MBC and MC derived from the new C （straw or biochar） ranked as Soil＋Straw〉Soil＋B250〉Soil＋B350, whilst significant higher SOC from the new C as Soil＋B250〉Soil＋Straw≈Soil＋B350. Compared to Soil, DOC and MBC derived from the native soil were decreased under straw or biochar addition, whilst MC from the native soil was increased under straw addition but decreased under biochar addition. Meanwhile, native SOC was similar among the treatments, irrespective of the straw or biochar addition. Compared to Soil, significant higher total DOC and total MBC were under Soil＋Straw, but not under Soil＋B250 and Soil＋B350, whilst significant higher total MC and total SOC were under straw or biochar addition, except for MC under Soil＋B350. Our results demonstrated that the application of biochar to soil may be an appropriate management practice for increasing soil C storage.

Development of the straw biochar returning concept in China

Biochar produced from straw has been shown to improve soil physicochemical properties.This review introduces the fundamental concepts,the broad applications,and underlying theory of straw biochar returning.Current developments in biochar industry and the production practices prevalent among enterprises in China are critiques.This review analyzes current knowledge gaps,challenges,and opportunities in the industrial application of straw biochar returning.Biochar standards,the quantitative and qualitative analysis methods for biochar,and high-value-added products that are based on biochar are critically examined with goal of providing recommendations for future studies.We propose production and modification of biochar that is application oriented to enhance its fitness for purpose as well as long-term and large-space-scale field study to better understand its impact on soil properties and ecotoxicology.Finally,we make prospects for the future development of SBR,including constructing a standard system about straw biochar returning and promoting self-discipline of biochar industry and the establishment of a biochar-based agricultural production model.

Insights on mechanisms of aluminum phytotoxicity mitigation by canola straw biochars from different regions

To better understand the amendment effects and mechanisms of aluminum(Al(Ⅲ))phytotoxicity mitigation by differ-ent regional crop straw biochars,wheat seedling root elongation trials were conducted.The contributions of liming effect,oxygen-containing surface functional group adsorption,and oxyanions precipitation to Al(Ⅲ)phytotoxicity mitigation by Ca(OH)_(2),pristine and ash-free canola straw biochar were evaluated.The results indicated that biochars derived from canola straw collected from four different regions(Yingtan,Xuancheng,Nanjing,and Huaiyin)caused 22-70%wheat seedling root elongation,which might be linked to liming effect.Incorporation of the corresponding ash-free biochars caused 15-30%elongation,which could be attributed to the surface functional group adsorption.About 0-60%of changes could be explained by Al(Ⅲ)precipitation with inorganic oxyanions.These findings provide new insights into the physicochemical properties,potential applications,efficiencies,and underlying mechanisms of crop straw biochar in alleviating Al(Ⅲ)phytotoxicity,which is dependent on the cultivation soil,and indicate similar application of crop straw biochar for acidic soil amelioration,contaminated soil remediation,and arable soil improvement.

Effects of different C/N ratios on the maturity and microbial quantity of composting with sesame meal and rice straw biochar

The purpose of this paper was to study the effects of different C/N ratios on the maturity and microbial quantity of com-posting with sesame meal and rice straw biochar.Rice straw was calcined into biochar as raw materials composting with sesame meal for 30 days,referring to Chenfu Agricultural Book in Sōuthern Song Dynasty(1127-1279 A.D.).Sesame meal was used to adjust the C/N ratio of compost,and three treatments were designed in the experiment,which were C/N ratios of 15,20 and 30,respectively.The results showed that C/N ratio of 20 was beneficial for promoting the temperature rise,the removal of water,the degradation of organic carbon,and the decrease of microbial quantity.The C/N ratio of 20 was beneficial to the compost maturity(T value was 0.47,final GI was 99.67%).The results of Pearson correlation analysis showed that C/N ratio was positively correlated with moisture content,total organic carbon and negatively correlated with germination index,indicating that high C/N ratio was beneficial to water removal and total organic carbon degradation.Therefore,we suggest that the suitable C/N ratio of rice straw biochar and sesame meal is 20.At the same time,we have proved that the composting method in Southern Song Dynasty is feasible,which is of great significance to understand the development of composting in China.

Steam explosion of crop straws improves the characteristics of biochar as a soil amendment

Five crop straws (wheat, rice, maize, oil-rape, and cotton) were first steam-exploded for 2 min at 210℃, 2.5 MPa and then pyrolyzed at 500℃ for 2 h. Steam explosion (SE) induced 47–95% and 5–16% reduction of hemicellulose and cellulose, respectively, in the crop straws. The biochars derived from SE-treated feedstocks had a lower specific surface area (SSA) and pore volume, compared to those from pristine feedstocks, with one exception that SE enhanced SSA of oil-rape straw biochar by approximately 16 times. After SE, biochars had significant higher anion exchange capacity (AEC) (6.88–11.44 cmol kg–1) and point of zero net charges (PZNC) (pH 3.61–5.32) values. It can thus be speculated that these biochars may have higher potential for anions adsorption. In addition, oil-rape straw might be suitable to SE pretreatment for preparing biochar as a soil amendment and sorbent as well. Further work is required for testing its application in soil.

Effects of straw and biochar addition on soil nitrogen,carbon,and super rice yield in cold waterlogged paddy soils of North China

The additions of straw and biochar have been suggested to increase soil fertility, carbon sequestration, and crop produc- tivity of agricultural lands. To our knowledge, there is little information on the effects of straw and biochar addition on soil nitrogen form, carbon storage, and super rice yield in cold waterlogged paddy soils. We performed field trials with four treatments including conventional fertilization system （CK）, straw amendment 6 t ha^-1 （S）, biochar amendment 2 t ha^-1 （C1）, and biochar amendment 40 t ha^-1 （C2）. The super japonica rice variety, Shennong 265, was selected as the test Crop. The results showed that the straw and biochar amendments improved total nitrogen and organic carbon content of the soil, reduced N2O emissions, and had little influence on nitrogen retention, nitrogen density, and CO2 emissions. The S and C1 increased NH4^＋-N content, and C2 increased NO3^--N content. Both S and C1 had little influence on soil organic carbon density （SOCD） and C/N ratio. However, C2 greatly increased SOCD and C/N ratio. C1 and C2 significantly improved the soil carbon sequestration （SCS） by 62.9 and 214.0% （P〈0.05）, respectively, while S had no influence on SCS. C1 and C2 maintained the stability of super rice yield, and significantly reduced CH4 emissions, global warming potential （GWP）, and greenhouse gas intensity （GHGI）, whereas S had the opposite and negative effects. In summary, the biochar amendments in cold waterlogged paddy soils of North China increased soil nitrogen and carbon content, improved soil carbon sequestration, and reduced GHG emission without affecting the yield of super rice.

Effect of Crop-Straw Derived Biochars on Pb(Ⅱ) Adsorption in Two Variable Charge Soils

Two variable charge soils were incubated with biochars derived from straws of peanut, soybean, canola, and rice to investigate the effect of the biochars on their chemical properties and Pb（II） adsorption using batch experiments. The results showed soil cation exchange capacity （CEC） and pH significantly increased after 30 d of incubation with the biochars added. The incorporation of the biochars markedly increased the adsorption of Pb（II）, and both the electrostatic and non-electrostatic adsorption mechanisms contributed to Pb（II） adsorption by the variable charge soils. Adsorption isotherms illustrated legume- straw derived biochars more greatly increased Pb（II） adsorption on soils through the non-electrostatic mechanism via the formation of surface complexes between Pb（II） and acid functional groups of the biochars than did non-legume straw biochars. The adsorption capacity of Pb（II） increased, while the desorption amount slightly decreased with the increasing suspension pH for the studied soils, especially in a high suspension pH, indicating that precipitation also plays an important role in immobilizing Pb（II） to the soils.

Effects on soil quality of biochar and straw amendment in conjunction with chemical fertilizers

The objective of this study was to evaluate the effects on chemical and microbiological properties of paddy soil of short-term biochar,straw,and chemical fertilizers compared with chemical fertilization alone.Five soil fertilization treatments were evaluated：regular chemical fertilizers（RF）,straw＋regular chemical fertilizers（SRF）,straw biochar＋regular chemical fertilizers（SCRF）,bamboo biochar（BC）＋regular chemical fertilizers（BCRF）,and straw biochar＋70%regular chemical fertilizers（SC＋70%RF）.Their effects were investigated after approximately 1.5 years.The soil p H and cation exchange capacity（CEC）were significantly higher in biochar-treated soils.The soil phosphorous（P）and potassium（K）contents increased with biochar application.The soil Colwell P content was significantly increased with the addition of straw biochar in the treatments of SCRF and SC＋70%RF.The oxygen（O）：carbon（C）ratio doubled in BC picked from the soil.This indicated that BC underwent a significant oxidation process in the soil.The denaturing gradient gel electrophoresis（DGGE）fingerprints of microbial communities differed among the treatments.Soils with added biochar had higher Shannon diversity and species richness indices than soils without biochars.The results suggest that biochar can improve soil fertility.

Simultaneous removal of cadmium and sulfamethoxazole from aqueous solution by rice straw biochar

The simultaneous sorption behavior and characteristics of cadmium (Cd) and sulfamethoxazole (SMX) on rice straw biochar were investigated. Isotherms of Cd and SMX were well modeled by the Langmuir equation (R2 >0.95). The calculated maximum adsorption parameter (Q) of Cd was similar in single and binary systems (34129.69 and 35919.54 mg/kg, respectively). However, the Q of SMX in a binary system (9182.74 mg/kg) was much higher than that in a single system (1827.82 mg/kg). The presence of Cd significantly promoted the sorption of SMX on rice straw biochar. When the pH ranged from 3 to 7.5, the sorption of Cd had the characteristics of a parabola pattern with maximum adsorption at pH 5, while the adsorption quantity of SMX decreased with increasing pH, with maximum adsorption at pH 3. The amount of SMX adsorbed on biochar was positively correlated with the surface area of the biochar, and the maximum adsorption occurred with d 250 biochar (biochar with a diameter of 150-250 μm). Scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) showed that the removal of Cd and SMX by rice straw biochar may be attributed to precipitation and the formation of surface complexes between Cd or SMX and carboxyl or hydroxyl groups. The results of this study indicate that rice straw biochar has the potential for simultaneous removal of Cd and SMX from co-contaminated water.

Soil N transformation and microbial community structure as affected by adding biochar to a paddy soil of subtropical China

We have had little understanding on the effects of different types and quantities of biochar amendment on soil N transformation process and the microbial properties. In this study, various biochars were produced from straw residues and wood chips, and then added separately to a paddy soil at rates of 0.5, 1 and 2% （w/w）. The effects of biochar application on soil net N mineralization and nitrification processes, chemical and microbial properties were examined in the laboratory experiment. After 135 d of incubation, addition of straw biochars increased soil pH to larger extent than wood biochars. The biochar-amended soils had 37.7, 7.3 and 227.6% more soil organic carbon （SOC）, available P and K contents, respectively, than the control soil. The rates of net N mineralization and nitrification increased significantly as biochars quantity rose, and straw biochars had greater effect on N transformation rate than wood biochars. Soil microbial biomass carbon increased by 14.8, 45.5 and 62.5% relative to the control when 0.5, 1 and 2% biochars （both straw- and wood-derived biochars）, respectively, were added. Moreover, biochars amendments significantly enhanced the concentrations of phospholipid fatty acids （PLFAs）, as the general bacteria abundance increased by 161.0% on average. Multivariate analysis suggested that the three rice straw biochar （RB） application levels induced different changes in soil microbial community structure, but there was no significant difference between RB and masson pine biochar （MB） until the application rate reached 2%. Our results showed that biochars amendment can increase soil nutrient content, affect the N transformation process, and alter soil microbial properties, all of which are biochar type and quantity dependent. Therefore, addition of biochars to soil may be an appropriate way to disposal waste and improve soil quality, while the biochar type and addition rate should be taken into consideration before its large-scale application in agro-ecosystem.

4年单季生物炭与秸秆还田对潮土土壤团聚体及有机碳影响

【目的】阐明连续单季秸秆与生物炭还田对土壤团聚体及有机碳的影响,对于秸秆资源更加合理地应用于农田土壤改良及土壤质量提升至关重要。【方法】以鲁西平原冬小麦-夏玉米轮作土壤为研究对象,以不添加秸秆与生物炭为对照(CK),研究2019—2023年冬小麦单季0.5倍(S0.5,3.80 t/hm^(2))、1.0倍(S1.0,7.60 t/hm^(2))、1.5倍(S1.5,11.40 t/hm^(2))和2.0倍(S2.0,15.20 t/hm^(2))玉米秸秆与同倍数玉米秸秆炭化还田(B0.5、B1.0、B1.5、B2.0,生物炭量分别为1.14、2.28、3.42、4.56 t/hm^(2))对冬小麦季耕层土壤团聚体及有机碳影响。【结果】生物炭与秸秆还田均可降低土壤体积质量,0~10 cm土层B2.0处理及10~20 cm土层B1.5处理土壤体积质量较CK对应土层降低最多,分别显著降低9.08%和7.97%。2种秸秆还田方式均在一定程度上促进了土壤团聚体的增加,对˃5 mm粒级土壤团聚体改善效果最佳,而1~2 mm粒级土壤团聚体最差。与CK相比,0~10 cm土层中B1.0处理˃5 mm粒级土壤团聚体量增加最多,显著增加107.35%,10~20 cm土层中S1.5处理˃5 mm粒级土壤团聚体量增加最多,显著增加106.63%。除S1.5、B0.5处理分别降低了0~10 cm土层˂0.25 mm粒级、10~20 cm土层1~2 mm粒级团聚体土壤有机碳量(SOC)外,其余生物炭与秸秆还田均促进了SOC的增加,且SOC大致随秸秆及生物炭还田量的增加而增加。【结论】单季玉米秸秆及玉米秸秆炭化还田均可降低耕层土壤体积质量,提高各粒级水稳性团聚体及有机碳量。综合考虑,建议冬小麦季单季采用1.5~2.0倍(3.42~4.56 t/hm^(2))的玉米秸秆炭化还田是该区提升土壤质量较为合理的秸秆还田方式。

Soil organic carbon associated with aggregate-size and density fractions in a Mollisol amended with charred and uncharred maize straw

Straw return has been strongly recommended in China,whereas applying biochar into soil is considered to provide more benefits for agriculture as well as the environment.In this study,a five-year(2011-2015) field experiment was conducted to evaluate the effects of uncharred maize straw amendment(MS) and charred maize straw amendment(charred MS) on organic carbon(C) contents in bulk soil and in various soil aggregate-size and density fractions.Compared to no amendment(CK),the bulk soil organic C content significantly improved by 9.30% for MS and by 23.4% for charred MS.Uncharred and charred maize straw applied annually at a consistent equal-C dosage resulted in 19.7 and 58.2% organic C sequestration efficiency in soil,respectively,after the five years of the field experiment.The percentages of macroaggregates(>0.25 mm) and occluded microaggregates(0.25-0.053 mm) obviously increased by 7.73 and 18.1% for MS and by 10.7 and 19.6% for charred MS,respectively.Moreover,significant incremental increases of 19.4 and 35.0% in macroaggregate-associated organic C occurred in MS and charred MS,respectively.The occluded microaggregates associated organic C significantly increased by 21.7% for MS and 25.1% for charred MS.Mineral-associated organic C(<0.053 mm) inside the macroaggregates and the occluded microaggregates obviously improved by 24.7 and 33.3% for MS and by 18.4 and 44.9% for charred MS.Organic C associated with coarse particulate organic matter(POM) within the macroaggregates markedly increased by 65.1 and 41.2% for MS and charred MS,respectively.Charred MS resulted in a noteworthy increment of 50.4% for organic C associated with heavy POM inside the occluded microaggregates,whereas charred MS and MS observably improved organic C associated with heavy POM inside the free microaggregates by 36.3 and 20.0%,respectively.These results demonstrate that uncharred and charred maize straw amendments improve C sequestration by physically protecting more organic C in the macroaggregates and the occluded microaggregates.Compared to the feedstock straw amendment,charred maize straw amendment is more advantageous to C sequestration.

Characterization of biochars produced from seven biomasses grown in three different climate zones

The characterization of biochars produced from seven feedstocks(four crop straws: cotton stalks, wheat stalks, rape stalks and corn stalks; three hardwoods: Salix babylonica Linn, Platanus orientalis and Robinia pseudoacacia) grown in three different climate zones(arid,semiarid and humid regions) were investigated for their potential as soil amendments. The results show that ash content, K+, Ca2+, Mg2+, CEC, Cl-, p H, and salinity are generally higher in the straw biochars(STR-BCs) than the hardwood biochars(HW-BCs). However, there is no significant distinction between the two categories of biochars in terms of surface acidity, surface basicity, TC, available phosphorus(A-P) or NH4+-N. The contents of K+, Na+,Ca2+, Mg2+, EC, Cl-of all 21 biochars increase in semiarid and arid regions in comparison to humid regions, while ash content, TC, CEC, p H, surface acidity, surface basicity,A-P and NH4+-N show no correlation to the climate. From the perspective of K+, CEC and the remediation of acidified soils, STR-BCs are preferable over HW-BCs as a soil amendment, while HW-BCs are more suitable than STRBCs in soils with a saline problem. EC, Na+and Clincrease with the water stress of the climatic regions, and the high saline ions of biochar in the arid regions indicate that biochars produced from local biomass, especially from crop residues, are at a high risk of exacerbating soil salinization. The big difference in the critical chemical properties, such as the saline ions, stresses that biochar should be taken on a regional basis as well as a biomass basis, with the general assumption that whether biochar as a soil amendment is good or bad is groundless.

Transformation mechanism of nutrient elements in the process of biochar preparation for returning biochar to soil

Returning biochar to soil is a heavily researched topic because biochar functions well for soil improvement. There is a significant loss of nutrients, which occurs during biochar preparation before biochar is returned to soil,thereby seriously undermining biochar＇s efficacy. Therefore, the transformation mechanisms of biochar p H,mass, nutrients and metals during pyrolysis under different atmospheres and temperatures were studied such that the best method for biochar preparation could be developed. Several conclusions can be reached：（1） a CO2 atmosphere is better than a N2 atmosphere for biochar preparation, although preparation in a CO2 atmosphere is not a common practice for biochar producers;（2） 350 ℃is the best temperature for biochar preparation because the amount of nutrient loss is notably low based on the premise of straw transferred into biochar; and（3） transforming mechanisms of pH, N, P and K are also involved in the biochar preparation process.

Effects of Straw Utilization Methods on Dry Matter Production and Yield of Japonica Rice in Northern China

To study the effects of straw utilization methods on dry matter production and yield of japonica rice in northern China,taking the super japonica rice Shennong 265 as the test material,using the planting method of seedling transplanting,setting four treatments,namely,the conventional production,directly returning straws to field(6 t/ha),returning straws to field at low amount of biochar(2 t/ha)and returning straws to field at high amount of biochar(40 t/ha),this paper analyzed the changes in production and yield of super japonica rice Shennong265.According to the experimental results,compared with the conventional production,after the straws were directly returned to the field,the dry matter accumulation of japonica rice was insufficient,and the leaf output rate and contribution rate were significantly reduced by 41.19%and 34.69%,respectively;the number of filled grains per panicle,1000-grain weight,and panicles per plant showed negative effect,leading to a decline in the yield;under the condition of returning straws to field at high amount of biochar,the dry matter accumulation showed a decline trend,both the leaf and stem sheath significantly reduced by 21.41%and 17.43%,and the number of filled grains per panicle also declined;under the condition of returning straws to field at low amount of biochar,the dry matter accumulation increased,and the leaf contribution rate increased by 11.68%,the number of filled grains per panicle,1000-grain weight,and panicles per plant showed positive effect,showing the potential of yield increase.In conclusion,returning suitable straw biochar to field(2 t/ha)is favorable for promoting the japonica rice production in northern China.

Sustainable Bio-Conversion of Rice Straw Waste into High Quality Organic Fertilizer

The aim of this study is to investigate the effect of different additives including biochar, effective micro-organisms (EM), animal manure and commercial microbial inoculants on the bioconversion of rice straw. Different compost piles were constructed, and each contained 50 kg of rice straw and mixture of natural rocks to enrich the compost nutritional value. The physical, chemical and biological parameters indicating the decomposition of organic material, maturation and quality of the organic fertilizer product were investigated during the composting process. A rapid increase in compost temperature was obtained in inoculated piles. All piles reached maturation after around 42 days. All analysis of the properties of the final compost products indicated that it was in the range of the matured level and can be used as organic fertilizer without limitation. The highest decomposition rate and highest organic fertilizer quality were obtained in the pile inoculated with EM and 10% biochar compared to other treatments.

秸秆生物炭与生物菌剂协同处理对土壤中重金属和抗生素的影响

以秸秆生物炭(S)和微生物菌剂(MA)为试材,采用高锰酸钾滴定、氨释放量、氯仿熏蒸-浸提法、PCR方法,研究了秸秆生物炭与生物剂(SM)协同处理对土壤的性质、酶活性、微生物量的影响,以及对铅(Pb)、镉(Cd)及其抗性基因(MRGs)、四环素(T)和抗生素抗性基因(ARGs)去除,以期为实现以废治废、优化资源的研究提供参考依据。结果表明:施用SM后,土壤的总有机碳(TOC)、总氮(TN)、总磷(TP)、速效磷(AP)得到有效的改善。过氧化氢酶(CAT)、脲酶(URE)、蔗糖酶(SUC)的活性分别比对照(CK)提高了36.00%、45.00%、53.00%。微生物碳(MBC)和微生物氮(MBN)、微生物磷(MBP)也得到相应的变化。Cd-Pb-SM组与Cd-Pb组相比,Cd、Pb的修复率分别为35.49%和20.09%;Cd-Pb-T-SM组与Cd-Pb-T组相比,Cd、Pb修复率分别为23.69%和25.57%。Cd-Pb-SM组与Cd-Pb组相比,cad D、pbrT的修复率分别为31.94%和30.11%;Cd-Pb-T-SM组与Cd-Pb-T组相比,cad D、pbrT修复率分别为29.19%和35.74%。T-SM、Cd-T-SM、Pb-T-SM、Pb-Cd-T-SM组与对应的T、Cd-T、Pb-T、Pb-Cd-T组相比,T的修复率分别为23.83%、24.03%、10.85%和19.08%;Cd-Pb-T-SM组与Cd-Pb-T组相比,tet A、tet M分别减少30.32%和31.71%。综上,秸秆生物炭协同生物菌剂可有效地改善土壤的结构和循环,促进土壤的酶活性,对重金属、抗生素的单一和多重污染均产生良好的消减作用。

小麦秸秆生物炭对孔雀石绿吸附性能的研究

为实现小麦秸秆的资源化利用,在不同温度下制备小麦秸秆生物炭,采用傅里叶变换红外光谱(FT-IR)、N2吸/脱附实验和扫描电镜(SEM)分别对生物炭表面的官能团、生物炭的孔隙结构和微观形貌进行表征,并利用其对孔雀石绿模拟废水进行吸附实验。结果表明:随着炭化温度的升高,生物炭中纤维素和半纤维素分解更彻底,芳香化增强;生物炭的总孔容和比表面积逐渐增大,平均孔径减小,微孔孔容增大。采用300℃下制备的生物炭对初始质量浓度为500 mg/L的孔雀石绿模拟废水进行吸附,当生物炭投加量为3 g/L时,在40℃时的吸附速率最快,2.5 h后基本达到吸附平衡,吸附去除率最高可达84.92%。吸附-脱附再生实验结果显示,经过3次循环后,生物炭的再生率达到92.70%,再生效果良好。以小麦秸秆为原料制备生物炭的方法简单,生物炭对孔雀石绿具有较高的吸附性能且可重复利用,这为小麦秸秆生物炭应用于印染废水处理提供理论依据和实践支撑。