Novel thiol-grafted composite of chitosan and rice straw biochar (TH@CT-BC): A two-step fabrication for highly selective adsorption of cadmium from contaminated water

In order to understand the resource utilization of plant biomass, five types of biomass materials were used to produce biochar to treat wastewater containing phosphorus. The phosphorus adsorption capacity of five materials was preliminarily compared through laboratory experiments, and two materials with strong phosphorus adsorption capacity were screened out. The physicochemical characteristics of the selected biochar were analyzed using scanning electron microscopy and a BET specific surface area analyzer, and the effects of different pH values on phosphorus adsorption of the biochar were investigated. Furthermore, the phosphorus adsorption characteristics of the selected biochar were analyzed via isothermal adsorption and adsorption kinetics models. The results showed that among the five biochar materials, only rice straw and corn straw biochar had the ability to adsorb phosphorus. The Langmuir isothermal adsorption curve showed that the adsorption capacity of rice straw biochar for phosphorus in wastewater was stronger than that of corn straw biochar, and the theoretical maximum adsorption capacity was as follows:rice straw biochar (9.78 mg·g-1)>corn straw biochar (0.39 mg·g-1). The specific surface area (148.30 m2·g-1) and total pore volume (0.11 cm3·g-1) of rice straw biochar were much higher than those of corn straw biochar (8.26 m2·g-1 and 0.03 cm3·g-1, respectively), and the contents of Mg, Ca, Fe, and Al were higher in rice straw biochar. The best pH for phosphorus adsorption of rice straw biochar and corn straw biochar was acidic. In different pH ranges (3.0-11.0), the phosphorus adsorption capacity of rice straw and corn straw biochar decreased with the increase in pH. These results indicated that rice straw biochar has strong phosphorus adsorption capacity and has a better application prospect in wastewater treatment.

Two field experiments were raised at Farm of El-Sirw Agriculture Research Station, Dammitta province, Egypt through 2018 and 2019 seasons. The present study was performed to compromise the influence of rice straw biochar and other two soil amendments of rice straw compost and gypsum on rice growth and yield of three contrasting rice varieties,Giza177 (salt sensitive variety), Giza 178 (salt tolerant variety) and Giza179 new (salt tolerant variety) under saline sodic soil. The field experiments were designed in spilt plot design with four replications. The three rice varieties were scattered in the main plot, whereas the amendment treatments; control, gypsum(G), rice straw compost (RS) and rice straw biochar (RSB) were put in the subplots. The tested rice varieties were significantly different in growth parameters, yield attributes and yields in both seasons. Giza 179 as a new salt tolerant variety provided the maximum values of rice growth characteristics and most of yield contributes and yields without significant difference with Giza178 were considering yields. Applying varying soil amendments greatly improved rice growth and yields in addition to yield attributes comparing to the control treatments. Rice straw biochar surpassed significantly other two amendments, particularly in the first season, meanwhile in the second seasonthe three soil amendments were equally in increasing grain yield. Thereby, rice straw biochar could be applied each two years but rice straw compost has to apply in two successive season to get its efficiency. Two field experiments were raised at Farm of El-Sirw Agriculture Research Station, Dammitta province, Egypt through 2018 and 2019 seasons. The present study was performed to compromise the influence of rice straw biochar and other two soil amendments of rice straw compost and gypsum on rice growth and yield of three contrasting rice varieties,Giza177 (salt sensitive variety), Giza 178 (salt tolerant variety) and Giza179 new (salt tolerant variety) under saline sodic soil. The field experiments were designed in spilt plot design with four replications. The three rice varieties were scattered in the main plot, whereas the amendment treatments; control, gypsum(G), rice straw compost (RS) and rice straw biochar (RSB) were put in the subplots. The tested rice varieties were significantly different in growth parameters, yield attributes and yields in both seasons. Giza 179 as a new salt tolerant variety provided the maximum values of rice growth characteristics and most of yield contributes and yields without significant difference with Giza178 were considering yields. Applying varying soil amendments greatly improved rice growth and yields in addition to yield attributes comparing to the control treatments. Rice straw biochar surpassed significantly other two amendments, particularly in the first season, meanwhile in the second seasonthe three soil amendments were equally in increasing grain yield. Thereby, rice straw biochar could be applied each two years but rice straw compost has to apply in two successive season to get its efficiency.

作物殘體經由燃燒後所產生之含炭物質，具有比表面積高、不易分解及良好的陰、陽離子交換容量，若施用於土壤中將會對於土壤基本性質、重金屬的移動和有機分子傳輸等具有影響。鉻在環境中主要以三價鉻﹝Cr(III)﹞及六價鉻﹝Cr(VI)﹞的形態存在，其中Cr(VI)的毒性和移動性都高於Cr(III)。現今受鉻污染之土壤常用的整治方法為添加化學還原劑(如，硫化鐵、亞鐵離子和零價鐵)將Cr(VI)還原為Cr(III)，近年已有研究藉由添加炭化之生物性資材還原Cr(VI)，然而土壤環境中存在許多變因，舉如土壤pH、有機質、氧化物及陰陽離子等，皆會影響炭化之生物性資材還原Cr(VI)之能力，因此本研究目的為探討添加稻稈生質炭(Rice-straw biochar; RB)到土壤中對土壤固定Cr(VI)之影響。 本研究選用兩種土壤，分別為陳厝寮系土壤(Chentsuo; Ce)(台中縣大肚鄉)及萬合系土壤(Wanho; Wa)(彰化縣埤頭鄉)，並添加5%的稻稈生質炭，以固液比為50 g L-1添加稻稈生質炭的土壤與10 mg L-1Cr(VI)溶液於pH 2.0-7.0以及未調整pH的環境中進行動力學反應。等溫吸附結果顯示，添加稻稈生質炭與否的陳厝寮和萬合系土壤在未調整pH的且低濃度Cr(VI)時，稻稈生質炭所固定的Cr(VI)佔土壤總固定量較大，顯示在低濃度的Cr(VI)污染情況時，土壤對於Cr(VI)的固定能力較佳。於動力學及土壤溶液中可溶性有機碳結果顯示，隨著溶液pH增加，陳厝寮及萬合系土壤對於Cr(VI)之固定和還原量隨之下降，可溶性有機碳濃度亦有上升趨勢。當溶液pH 7.0時，Cr(VI)仍有被還原的現象發生，表示可溶性有機碳將Cr(VI)還原為Cr(III)。當pH NO3- ≅ SO42- > Cl-。未來於土壤添稻稈生質炭若應用於低濃度Cr(VI)污染之土壤復育，對於Cr(VI)的固定和還原量是有影響性的。

Soil organic carbon content affects the stability of biochar in paddy soil

This research aims to compare fresh biochar and NPK-enriched biochar and their decomposition levels and nutrient absorption efficiency in acid soil with soybean. Factorial randomized block design was used in this experiment and consisted of two factors. The first factor, biochar source, comprised four levels: B0: biochar without NPK, B1: rice straw biochar + NPK, B2: soybean straw biochar + NPK, and B3: wood biochar + NPK. The second factor, biochar enrichment, comprised four levels: D1: 0.5 tons ha<sup>-1</sup>, D2: 2.5 tons ha<sup>-1</sup>, D3: 5.0 tons ha<sup>-1</sup>, and D4: 10 tons ha<sup>-1</sup>. Each treatment was replicated three times, yielding 48 experiment units. The results showed that biochar enrichment with NPK affected the decomposition level. The percentage of increasing decomposition in enriched wood biochar (0.09%) was lower than rice (0.28%) and soybean (0.53%) straw biochar. An increase in NPK absorbance efficiency and soybean dry weight was evident in NPK-enriched biochar. The highest N absorbance efficiency occurred in wood biochar (21%), followed by soybean and rice straw biochar, respectively, while the highest P and K absorbances were found in rice straw biochar (35% and 26%, respectively), followed by wood and then soybean biochar.

Removal of Pb(II) ions from aqueous solution by manganese oxide coated rice straw biochar A low-cost and highly effective sorbent

The biochar and microbial inoculant are commonly used amendments in soil improvement, but their effectiveness in protective agriculture is currently unclear. Based on this, this study takes the pepper vegetable greenhouse located in Zhuxi Town, Chongqing as the research object, and selects biochar prepared from corn straw and rice straw, as well as microbial inoculant, as the improvement materials. Five treatments were established, including corn straw biochar alone (CB), rice straw biochar alone (RB), microbial inoculant alone (CKM), combined corn straw biochar and microbial inoculant application (CBM), and combined rice biochar and microbial inoculant application (RBM), conventional fertilization was used as a control. This study explores the changes in soil physicochemical properties of protected vegetable production under different treatments at distinct time points (first, third, and fifth months after returning field) and soil depth (0-10cm and 10-20cm). The results demonstrated that the overall soil bulk density increased With the increase of returning time. There was no significant difference in the soil capillary porosity or mineral-associated organic carbon content (P > 0.05), whereas the other soil properties decreased with increasing return field time. In contrast, the soil bulk density (BD) increased with increasing soil depth. Except the capillary porosity, which exhibited no significant differences at different depths (P > 0.05), all the other soil properties demonstrated downward trends with increasing depth. After 5months of transplantation, the soil carbon pool management index of RBM treatment was higher than that of CBM treatment, with a 4.35% increase. The soil health index was 14.51% lower than that of CBM. However, the differences in soil carbon pool management index and soil health index between the two treatments did not reach a significant level. Overall, the RBM and CBM showed better improvement effects on soil carbon pool management index and soil health status, making them the better ratios for vegetable greenhouse farmland soil improvement in this study.

β-cyclodextrin functionalized biochars as novel sorbents for high-performance of Pb2+ removal.

Rice straw biochar mitigates N2O emissions under alternate wetting and drying conditions in paddy soil

ABSTRACTSalinization and alkalization contribute significantly to soil degradation. Rice ( Oryza sativa L.) cultivation is an effective approach to remediate saline‐alkali soil. However, how rice straw (RS), rice straw biochar (RSB), and rice straw ash (RSA) impact soil organic carbon (SOC) accumulation and stability in saline‐alkali soil remains unknown. Herein, SOC and SOC fractions contents in bulk soil and its particle‐ and aggregate‐size classes under RS, RSB, and RSA amendments and control with amendments (CK) were investigated by field experiment. Carbon‐13 nuclear magnetic resonance spectroscopy was used to evaluate bulk SOC chemical composition. The SOC and SOC fractions contents ranked as CK<RSA<RS<RSB. Aromatic C was higher whereas O‐alkyl C was lower in RSB relative to other treatments. The contents of SOC and SOC fractions in bulk soil were generally positively correlated with those in particle‐ and aggregate‐size classes as well as with aromatic C. Redundancy analysis showed that exchangeable sodium and electrical conductivity were the most significant factors in shaping SOC contents and chemical composition. The results indicated that RSB is more beneficial for SOC accumulation and stabilization as compared to RS and RSA. The primary mechanisms of SOC accumulation in RSB‐amended soil included physical protection afforded by aggregate classes, chemical protection mediated by silt and clay fractions, and biochemical protection with recalcitrant aromatic C. Our findings suggest that converting RS into RSB and the subsequent application of this biochar have the potential for improving soil quality in saline‐alkali paddy field.

Impacts of biochar addition on rice yield and soil properties in a cold waterlogged paddy for two crop seasons

Inhibition of polycyclic aromatic hydrocarbon (PAHs) release from sediments in an integrated rice and crab coculture system by rice straw biochar

Adsorption kinetics and isotherms of Cd2+ onto different types of biochar are studied in batch experiments. Three types of biochar (rice, wheat and corn straw biochar) and their phosphate or chitosan modified materials were used in this study. Results showed that Langmuir equation can better describe the adsorption isotherms of Cd2+ onto these biochars (r2 > 0.960). Among different types of biochars, rice straw biochar (RB) and its chitosan modified biochar (CRB) had highest adsorption capacity of Cd2+. RB, wheat straw biochar (WB) and their modified biochars were used to remediate Cd-contaminated soil. Soil pH values increased with the increasing of biochar dosage and chitosan modified biochar amended soil had the highest soil pH values. Contents of DTPA extractable Cd in soil decreased with the increase of biochar dosage and incubation time. Among different types of biochars, 5% CRB amended soil at 60 days of incubation had the lowest content of DTPA extractable Cd. This study showed that the application of modified biochars can effectively alleviate soil Cd contamination.

This research was conducted to determine the effect of giving sago dregs and rice straw biochar on growth and yield and to determine the correct dose of biochar for use in inceptisol soil. The research was conducted at the Experimental Garden of the Research Institute for Various Nut and Tuber Crops (BALITKABI) IP2TP Jambegede, Jl. Agriculture, No.6 Kemiri Village, Kepanjen District, Malang Regency – East Java. The design used was a Randomized Block Design (RBD), which consisted of 6 treatments and was repeated four times. There are 6 treatments, namely: P0 = without biochar; P1 = 100% rice straw biochar; P 2 = sago dregs biochar 100%; p 3 = sago pulp biochar 75% + rice straw biochar 25%; p 4 = sago pulp biochar 50% + rice straw biochar 50%; p 5 = sago pulp biochar 25% + rice straw biochar 75%. Observations included plant height, number of leaves, leaf area, seed weight per plant, and weight of 100 seeds. Data were analyzed using a variance test (Anova) by MS Excel. The results of this research show that the administration of sago dregs biochar and rice straw has a significant effect on yield and growth, where treatment (P3) with a mixture or combination of 75% sago dregs + 25% rice straw biochar, gave the best response compared to other treatments, with results reached 1.64 t.ha-1. Thus, a mixture or combination of 75% sago dregs biochar + 25% rice straw biochar can be used in Inceptisol.

Industrial activities can contribute to the heavy metal accumulation in soils, which could potentially threaten human health, agricultural crop productivity and the environment. This research was conducted to use metal uptake and spectroscopic analysis (X-Ray Diffraction (XRD), Energy Dispersive spectroscopy by X-rays (EDX) and Fourier Transmission Infrared Spectroscopy (FTIR) to evaluate the effect of application of both rice straw biochar and compost with different ratios on heavy metal immobilization in the canola plants grown in the contaminated soil. The results showed that the Cd, Pb, Ni and Zn uptake in the root and shoot of canola plants significantly decreased with the addition of rice straw compost (RC) and biochar (RB) to contaminated soil. The addition of 1% mixture of RC and RB gives the most effective immobilizing metals as 100% and 74.2%, reduction in Cd and Pb accumulation by canola shoots, respectively. The biochar and compost obtained from rice straw showed high carbon content, silica and a high absorption character. The use of spectroscopic analysis observed the precipitation, inner-sphere complex reaction and electrostatic attraction are the dominating mechanism for heavy metal immobilization with organic amendments. Our results indicate that the metal uptake is considered to be the effective tool to assess the efficiency of immobilizing agents on metal phyto-availability.