Trace element evaluation of rice and husk by INAA

An instrumental neutron activation analysis technique has been utilized to study the prevailing levels of certain inorganic trace elements in different varieties of rice produced in Pakistan. The data have been compared with those of other countries. The elemental ratios within rice and rice to husk have been computed to evaluate indirectly the impact of soil and environment on the rice crops. The dietary spectum for the inhabitants of Rawalpindi/Islamabad areas has been evaluated by estimating the daily intake and comparing with allowances suggested in the literature.     

Effect of the Coating of the Polymer Blend (Polyacrylamide/PEG 6000) on the Efficiency of Rice Husk as a Pesticide Carrier

In recent years the utilization of fibers and powders derived from agricultural sources has become a subject of interest. However, they have been exploited only from an engineering point of view, and the strong ability of agricultural wastes as a carrier for agrochemical formulations has been ignored. A study has been made on the possibility of using such an agrochemical waste, namely rice husk, which is readily available and biodegradable, as a carrier for pesticide formulation. The solid formulations were prepared by adsorbing deltamethrin on the rice husk. The deltamethrin‐adsorbed rice husk is then coated with the polymer blend of Polyacrylamide and PEG 6000 in varying ratios between the deltamethrin‐adsorbed rice husk and the polymer blend. The formulations were characterized by analytical methods such as FTIR and XRD techniques. Important physical properties from the formulation standpoint, such as solubility, dispersion stability, and wettability, were studied.     

Determination of Au,Sb, As,Br, Na,K, Cd,Mn and Cl in rice from Vietnam by neutron activation analysis

Gold, antimony, arsenic, bromine, sodium, potassium, cadmium, manganese and chlorine were determined by neutron activation analysis in various rice seed, brand layer and husk from Vietnam. The following concentration values were found: Au 0.05–0.28 ppm, Sb 0.05–1.08 ppm, As 0.08–0.94 ppm, Br 0.82–6.72 ppm, Na 16.71–25, 71 ppm, K 2582–5163 ppm, MN 19.26–33.43 ppm, Cd 0.51–2.42 ppm and Cl 205.20–828.61 ppm in rice seed. These elements were also determined in brand layer and rice husk. Statistically significant differences /t=0.05/ in Au, Sb, Cd contents were detected in rice seed and rice husk, as well as brand layer with rice husk.     

生物质高级再燃脱硝的影响因素与元素释放特性

以稻壳(RH)、梧桐叶(PTL)和木屑(SD)为对象,利用携带流脱硝实验装置,研究了生物质种类、再燃反应温度(t2)、再燃区化学计量比(SR2)、喷氨位置、水蒸气以及添加剂等对生物质高级再燃(AR)脱硝效率的影响,分析了高级再燃过程中钾和氯等元素的释放特性。结果表明,在t2为850~1 150℃,随着t2升高,生物质高级再燃脱硝效率呈现先上升后下降的趋势。在SR2为0.5~1.0,随着SR2增加,稻壳高级再燃脱硝效率呈现先增加后降低的趋势。停留时间为0.4~1.0 s,氨气添加位置对稻壳高级再燃脱硝效率有一定的影响,但其效果并不明显。烟气中水蒸气含量(0~15%)可提高稻壳高级再燃的脱硝效率,而且可拓宽脱硝温度窗口。不同再燃温度下,4%水蒸气含量模拟烟气的脱硝效率最大。添加剂(Fe2O3、KCl、NaCl和CaO)对稻壳高级再燃脱硝均有促进作用,其中,Fe2O3促进作用最为显著。在稻壳高级再燃过程中,氯和钾元素释放率分别达到95.0%和59.8%以上。     

Techno-economic feasibility of biochar as biosorbent for basic dye sequestration

Biochar has a global scientific attention for its ability to remove toxic elements from wastewaters. However, due to the disparity between practical short-term agronomic benefits and aspirations of biochar as an everlasting sustainable bio sorbent for the adsorption process, economic assessments of biochar have yet to be established. In this context, the current study, an economic approach of the biochars derived from agricultural wastes (Coconut shell, Groundnut Shell and Rice husk) for the removal of Basic Red 09 from wastewaters were demonstrated. Batch adsorption experimental set up was used to carry out the adsorption process. At equilibrium batch adsorption conditions, the maximum adsorption capacity of the biochars were 10, 46.3, and 44 ​mg/g for coconut shell, groundnut shell, and rice husk based biochars, respectively. A complete cost assessment was carried out for the agro-waste biochars for their adsorption performance. The biochars derived from groundnut shell and rice husk were shown to be the most cost effective for the Basic Red 09 sequestration from wastewater. The eco-friendly characteristics of these low-cost adsorbents for industrial applications were also discussed.     

钾元素对生物质及其三组分热解的影响

采用机械混合法将KCl加入到纤维素、半纤维素、木质素以及稻壳和稻壳模拟物等生物质中,得到了一系列不同K含量的生物质样品,通过热重(TG)实验考察了K元素对生物质热解特性的影响.结果表明,K元素对生物质三组分热解特性的影响比较复杂,纤维素的最大热解失重速率随着KCl添加量的增加而降低,但KCl对半纤维素和木质素热解特性的影响不显著.无论是否添加KCl,模拟生物质的热解特性均可以认为是三组分热解的简单叠加.但酸预处理稻壳三组分间的稳定结构,导致其DTG曲线在300 ℃左右的热解峰由稻壳模拟物的尖峰变为肩峰,其热解焦炭收率也比稻壳模拟物的略低.此外,实验还采用浸渍法向酸预处理稻壳中添加了KCl.TG实验结果表明,K元素的存在对生物质热解具有一定的催化作用,但KCl的添加方式不同,生物质的热解特性有明显差别,生物质样品经机械混合添加KCl后,其热解焦炭收率呈下降趋势(纤维素除外),浸渍法添加的KCl导致酸预处理稻壳的最大热解失重速率和焦炭收率升高.     

A Study on the thermal destruction of rice husk in air and nitrogen atmosphere

The methods of X-ray analysis, infrared spectroscopy, differential thermal analysis and scanning electron microscopy were used in this study. The objects of the experiments were rice husk obtained during processing of rice, variety Krasnodarski 424. The rice husk was burnt in air and in non-oxygen medium at several burning temperatures. The color of the oxidized product was stipulated by the burning temperature. The X-ray analysis showed that the amorphous SiO₂ present in the rice husk begins to crystallize in the form of α-cristobalite at 850°C. Using differential thermal analysis, the thermal destruction of rice husk was studied in air and nitrogen media and the initial and final temperatures of the process were determined. The silica distribution was examined by scanning electron microscopy and infrared spectroscopic techniques.     

Thermal kinetics and morphological investigation of alkaline treated rice husk biomass

Agro waste bio mass are creating challenges for environment in term of air pollution due to improper disposal. Rice milling is the process in which rice husk is produced as by-product. The agro-waste rice husk has tremendous potential to be used either in its raw form or in ash form. The inherent component of this waste cellulose provides enhanced properties in a reinforced composite when used as filler. Rice husk is the hard outer layer and covering rice seed, which makes reinforcement challenging in its original form. Fiber surface treatment significantly improves adhesion with matrix and various thermo chemical properties of filler as well as of composites. NaOH treatment is cost-effective and it ensures the adhesion with matrix by removal of hemicellulose and lignin. The chemical treatment of agro-waste (rice husk) is performed with 5% alkali solutions of NaOH in water. Results are compared with the properties of untreated rice husk for thermal and morphological characterizations. In the present work, we are trying to quantify the impact of chemical treatment on rice husk thermal decomposition and its kinetics. Thermogravimetric analysis and kinetics study of thermal degradation, provide key input towards pyrolysis pattern of rice husk, while FTIR and SEM analysis provide the prospects of this bio filler using a reinforcing agent to develop green composite and productive disposal. The FTIR data helps to find the possibilities of blending different bio fillers and natural fibers to find suitable reinforcing substances. The average activation energy of treated fiber is noted as 137.95 by KAS method and 108.08 by FWO method as compared to 55.56 by KAS method & 54.26 by FWO method for untreated rice husk.     

A simple template-free sol–gel synthesis of spherical nanosilica from agricultural biomass

Mesoporous silica nanoparticles with a spherical morphology have been synthesized from rice husk (agricultural biomass) by a simple, template-free synthetic approach, which was carried out via sol–gel technique at ambient condition. Transmission electron micrographs revealed the formation of spherical silica nanoparticles with an average diameter of 50.9 nm. From the nitrogen adsorption–desorption analysis, the rice husk silica shows a high specific BET surface area of 245 m² g⁻¹. The silica nanoparticles have a narrow pore size distribution of 5.6–9.6 nm.     

Studies on potential utilization of rice husk char in blend with lignite for cocombustion application

Combustion behavior of Indian lignite sample blended with rice husk chars (prepared at low temperature) has been examined in this study through simultaneous differential scanning calorimetry (DSC) and thermogravimetric analysis (TG) technique. Range of inputs obtainable by characteristic TG–DSC parameters has been utilized to arrive at important conclusions and observations in respect of ideal selection of blend proportion, proper utilization of the blend combination, etc. Deviations of experimental mass loss pattern (TG) and of rate curve (DTG) from corresponding expected theoretically calculated pattern have also been noted for different blends to examine possible advantageous or disadvantageous effects. As per the observations recorded, use of biomass char in blends (with lignite) was found to be very much beneficial and its proportion in the blends may be restricted to a level of 40 % by mass to extract maximum benefits in burning performance. This paper also focuses specific advantages of use of rice husk char in place of raw rice husk for cocombustion applications. Moreover, the importance of heat release pattern to assess compatibility of a fuel mix with existing boiler design and also to workout fresh boiler design for cocombustion application has been discussed in this paper.     

Effect of removing silica in rice husk for the preparation of activated carbon for supercapacitor applications

The significant influence of silica inside rice husk in the preparation and electrochemical performances of activated carbon are investigated. The removing of silica results in high mesoporous ratio and good rate capability.     

Efficient production of nanoporous silicon carbide from rice husk at relatively low temperature

Nanoporous silicon carbide with a specific surface area of up to 186.45 m² g⁻¹ has been efficiently synthesized from waste rice husk using a magnesiothermic reduction at 950 °C as a key step. Throughout the entire process, the recovery rates of silicon, potassium and phosphorus from rice husk can reach 88.46, 91.5 and 65.5%, respectively. Turning rice husk waste into a real treasure, this promising method for producing porous SiC protects the environment and brings economic benefits.     

Preparation and characterization of rice husk/ferrite composites

<正>A novel ferrite composite using rice husk as substrate has been prepared via high temperature treatment under nitrogen atmosphere.The rice husk substrate consists of porous activated carbon and silica,where spinel ferrite particles with average diameter of 59 nm are distributed.The surface area of the composite is greater than 170 m~2 g~(-1) and the bulk density is less than 0.6 g cm~(-3).Inert atmosphere is indispensable for the synthesis of pure ferrite composites,while different preparation temperatures of above 600℃result in composites with similar structures and morphologies.Due to the presence of ferrite particles,this novel composite shows enhanced adsorption ability for acid orangeⅡ.     

酸预处理对生物质热裂解规律影响的实验研究

在自制的热裂解机理实验台上进行了不同酸处理对稻壳以及白松的热裂解影响实验研究。经过盐酸浸泡后,稻壳中的金属离子含量明显降低;经盐酸洗涤后的稻壳热裂解焦油产量升高,由原始物料时的41.74%增加到7%盐酸洗涤后的52.88%,而气体和焦炭产量相应降低,并且随着盐酸浓度的增加,对应的趋势更加明显。酸洗涤后稻壳热裂解气体产物主要由CO和CO₂组成,其产量相比原样都有所降低;不同种类的酸对生物质热裂解规律的影响存在差异,盐酸因其去离子效果最好而对生物质热裂解产物分布影响最强;对白松原样以及酸洗后白松的微观结构进行了电镜分析,结果发现,硫酸对白松的微观结构产生了明显的影响。     

Synthesis,Characterization, and Catalytic Behavior of Bamboo Rice Husk Ash

In this paper, we report the use of bamboo rice husk ash as an efficient, greener, reusable, and biodegradable heterogeneous catalyst for the synthesis of tetrahydro‐4H ‐chromene‐3‐carbonitriles via the one‐pot three‐component reaction of malononitrile with aromatic aldehydes and dimedone or 1,3‐cyclohexanedione. The formation of bamboo rice husk ash‐silica has been confirmed by several analytical techniques.     

川稻中铜铁锌锰四种微量元素的研究

四川是我国农业大省之一，水稻居其粮食作物的首位。而微量元素对生命有着重要的意义。本文对四川省稻米中铜、铁、锌、锰四种微量元素进行了分析研究，探索了它们大致的含量范围和糙米、精米及谷壳中微量元素含量的差异，证实了稻谷产量与以上四种微量元素总量间以及大米品质与铜、锌含量间呈正相关关系，也表明了大米中微量元素含量与土壤环境的正相关性。     

Study on the contents of trace rare earth elements and their distribution in wheat and rice samples by RNAA

The concentrations of 8 REE (La, Ce, Nd, Sm, Eu, Tb, Yb and Lu) in wheat and rice samples have been determined by RNAA. The contents and distributions of REE in each part of the plants (i.e. root, leaf, stem, husk and seed) and their host soils were studied, which included samples applied with rare earch elements in farming and control samples. The effects of applying rare earths on the uptake of REE by the plants and the REE accumulation in the grains on human health were also discussed in this paper.     

Hydrothermal synthesis of pollucite with soil and incineration ash for Cs immobilization and its immobilizing mechanism and leaching property

Journal of Radioanalytical and Nuclear Chemistry - A hydrothermal method has been developed to convert Cs-polluted soil (kaolin) mixed with incineration ashes of plants (rice husk ash) into...     

Adsorption of phenols from wastewater

The present work involves an investigation of the possible use of coal, residual coal, and residual coal treated with H3PO4 as a means of removal of phenol from wastewater. The study was realized using batch experiments, with synthetic wastewater having phenol concentration of 1000 ppm. Other low-cost adsorbents such as petroleum coke, coke breeze, rice husk, and rice husk char have also been used. The effect of system variables such as pH, contact time, and temperature has been investigated. The suitability of the Freundlich, Langmuir, and Redlich-Peterson adsorption models to the equilibrium data was investigated for each phenol-adsorbent system. The results showed that the equilibrium data for all the phenol-sorbent systems fitted the Redlich-Peterson model best. Kinetic modeling of removal of phenols was done using the Lagergren first-order rate expression. A series of column experiments were performed to determine the breakthrough curves.