Production and Characterization of Green Biosorbent Based on Modified Corn Cob Decorated Magnetite Nanoparticles

In most developing countries, particularly in the countries of sub-Saharan Africa, corn cobs are considered as waste polluting the environment during the harvest period of this cereal. In order to valorize this agricultural waste, high-performance, inexpensive and low-energy consumption magnetic bioadsorbents were prepared from corn cobs. The chemically activated raw corn cob was magnetized by coating the surface with magnetite nanoparticles. The prepared biosorbents were characterized by FT-IR, XRD, FE-SEM associated with EDX, HR-TEM, TG analysis, BET surface area analysis and XPS. The maximum specific surface area of 35.22 m2/g was reached. An attempt to use of these magnetic biosorbents for the removal of heavy metal like Cr(VI) from aqueous solution was envisaged.

Comparison of Dilute Organic Acid Pretreatment and a Comprehensive Exploration of Citric Acid Pretreatment on Corn Cob

As an important agricultural waste,corn cob is one of the most abundant lignocellulosic biomass.In this work,dilute acid pretreatment using seven different organic acids were compared for compositional analysis of corn cob.The first pKa of organic acids,influenced by the number and type of the side group and distance between two carboxylic groups,played a crucial role in the pretreatment effect.Citric acid was found to have better pretreatment performance than other tested dicarboxylic acids.Under the condition of 30 mM,160°C and 60 min,the level of xylose reached 22.64 g/L in pretreatment liquid,and the pretreated corn cob demonstrated the high enhancement of enzymatic hydrolysis up to 93.4%and the ethanol yield was 73.6%.

Development of Silica Nanoparticle from Corn Cob Ash

Silica from corn cob ash (CCA) was extracted via sol-gel, and nanostructured with templating concept, these resulted in silica nanoparticle. Silica and mineral contents of CCA were determined by X-ray fluorescence (XRF). X-ray diffraction (XRD) patterns revealed amorphous nature of extracted silica. Fourier transform infrared (FTIR) data indicated the presence of siloxane and silanol groups. X-ray diffraction (XRD) of nanostrurtured silica reviled average particle size of 54 nm, Scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM/EDS) study indicates the particles to possess disorder morphology with the particle attached to each other through grain boundary to form agglomerated structure, and SEM analysis shows that particle size varies from 44 nm - 98 nm in diameter, with an average diameter of 55nm. EDS spectrum confirms SiO2.

A Research on the Usage of Corn Cob in Producing Lightweight Concrete

In this study, the possibility of using corn cobs as an organic aggregate in producing lightweight concrete has been investigated. First, some important physical properties of corn cob have been determined in the laboratory. These properties are as follows: weight to volume ratio (unit weight), water absorption rate and granulometric analysis. Later on, 4 concrete mixtures have been prepared according to the workability of concrete and standards specified in Turkey. After that, unit weight, heat transmissibility coefficient and 28-day pressure strength of these 4 concrete samples have been determined using machines measuring these properties. The 28-day pressure endurance value has been found between 1.4 - 56.25 kgf/cm2, heat transmissibility coefficient has been found between 0.19 - 0.35 Kcal/m∙h∙˚C and unit weight of samples have been found between 800 - 1520 kg/m3. Lastly, these properties of concrete samples have been compared with other lightweight materials being used in the construction of buildings.

Corn cob modified by lauric acid and ethanediol for emulsified oil adsorption

Corn cob is a naturally renewable material with developed micropore and hydrophobic characteristics, which enables it to show good oil adsorption capacity. In order to improve oil adsorption capacity, corn cob was modified with lauric acid and ethanediol. The structure of raw and modified corn cob was investigated using Fourier transform infrared(FTIR) spectroscopy, scanning electron microscopy(SEM), Brunauer-Emmett-Teller(BET) method, thermogravimetric analysis(TGA) and Ze Ta potential analyzer. The effects of p H level, adsorption time, adsorbent dosage, and initial oil concentration on oil absorbency of corn cob were studied. The results indicate that the modification significantly improved the lipophilicity of corn cob, making the modified corn cob with much better adsorption capacity on oil absorbency. Compared with raw corn cob, the maximum saturated adsorption capacity of modified corn cob is 16.52 mg/g at p H 5, and the increasing percentage is found to be 141%, which indicates that the modification causes a better adsorption capacity for oil removal. In addition, due to high oil adsorption capacity, affordable price and low secondary pollution, the modified corn cob could be considered promising alternative for the traditional oil adsorbent to clean up the emulsified oily water.

Binding Ability of Corn Cobs Hemicellulose toward Cadmium

Non-Starch Polysaccahride (NSP) is an agricultural byproduct containing of cellulose, hemicelluloses, and lignin. Hemicellulose has a hydroxyl functional group and carboxylic function on the monomer hemicellulose used as a binding ability for cadmium ion and hence as a pharmaceutical active ingredient to prevent cadmium toxicity. The purpose of this study is to isolate and evaluate hemicelluloses from corn cobs as a binding ability toward cadmium ion. The study is conducted by isolating the corn cobs in such way using 0.2 M NaOH, characterization of hemicellulose from corn cobs produced by Infra Red Spectrofotometry. Binding ability of corn cobs hemicellulose (CCH) was done in 3 ways. The first, it was by titrimetric with cadmium 3 mg/cm3 as a titrant and indicator of 0.05 N NaOH. The second, it was by in vitro test at pH 2 as a comparison to use pectin. The third, the in vivo test was conducted in 3 variations of treatment covering CCH 10 mg, 100 mcg of cadmium for 10 weeks. Assay of cadmium was conducted using atomic absorption spectrophotometry with flame at a wavelength of 228.8 nm. The research result showed that the highest yield of hemicellulose (12.04%) was obtained from delignication with 0.03 M NaOH in 60% ethanol and 3% H2O2, hemicellulose isolation with 500 cm3 of 0.2 M NaOH, and precipitation with 1:4 ratio of 10% acetic acid in 95% ethanol. Characteristics of CCH on infrared vibration methods provide vibrational hemicellulose in the region of 1820-1600 cm-1. It meant that the functional group carbonyl was present, and the vibration widened near 3400-2400 cm-1. It indicated that there was the functional group vibration region of hydroxyl. It also meant that there was carboxylic group and finger print at 1500-500 cm-1. Test results of the titrimetric holding ability showed that CCH was binding 100 mg of cadmium (46.17 ± 0.9256) mg or 46.17%. Binding ability test results at pH 2 showed that 300 mg of CCH yield was binding 30 mg cadmium of (26.68 ± 0.1490) mg or 88.93%. The results of in vivo tests showed that cadmium levels decreased by 95.05%. Based on the exposure, it can be concluded that the CCH isolation yields of 12.04% and can reduce cadmium levels in the blood. It means that the CCH can be used as a chelating agent of cadmium ions by in vitro and in vivo.

Effect of Varying Corn Cob and Rice Husk Ashes on Properties of Moulding Sand

The use of rice husk and corn cob ashes as aggregates for foundry moulding sand has been studied. 5-12.5 weight percent of rice husk and corn cob ashes were added to the sand mixture and the sand properties determined. A mixture of equal proportion of rice husk and corn cob ashes was also used. In each case, four weight percent water and clay were added to the sand mixture. Some of the properties of the sand tested are: permeability, green compression strength, dry compression strength, green shear strength, dry shear strength, moisture content and permeability. The results showed that the green compression strength, green shear strength, moisture content and permeability decrease with increase in the additives (rice husk ash, corn cob ash, and (50% rice husk and 50% corn cob ashes). While dry compression strength and dry shear strength increase with increase in weight percent of the additives.

Hypoglycemic effect and the mechanism of action of a polysaccharide from sweet corncob in a high-fat diet and streptozotocin-induced diabetic mice

Type 2 diabetes mellitus(T2DM)is a metabolic disease caused by a glycolipid metabolism disorder and isletβ-cell dysfunction.SCP-80-I is a biologically active water-soluble polysaccharide isolated from sweet corncob,an agricultural byproduct.The hypoglycemic effects of SCP-80-I on T2DM mice and its mechanisms were investigated in this study.SCP-80-I was found to significantly reduce blood glucose and lipid deposition levels in T2DM mice,as well as decrease serum leptin and increase adiponectin secretion.Interestingly,real time-polymerase chain reaction(RT-PCR)and Western blotting results revealed that SCP-80-I could regulate the expression of several glycolipid metabolisms and insulin secretion genes and proteins,including 5'-AMP-activated protein kinase(AMPK),carnitine palmitoyltransferase I(CPTI),and acetyl coenzyme A carboxylase(ACC)in the liver and AMPK,sirtuin1(Sirtl),peroxisome proliferator-activated receptorycoactivator-1(PGC-1α),and uncoupling protein 2(UCP2)in the pancreas.To have a hypoglycemic effect,SCP-80-1 regulated glycolipid metabolism and islet cell function in the liver by regulating the AMPK/AC C/CPT1 signaling pathway and the AMPK/Sirt1/PGC-1αand AMPK/Sirtl/UCP2 signaling pathways.These findings improve our understanding of polysaccharides derived from sweet corncob and the use of SCP-80-I in the production of hypoglycemic foods.

Recovery of NH4^＋ by corn cob produced biochars and its potential application as soil conditioner

NH4^＋ ion, a main pollutant in aquatic systems, not only causes eutrophication in rivers and lakes but also contributes to fish toxicity. In this study, an eco-friendly biosorbent was prepared from the pyrolysis of corn cob, a low-cost agricultural residue. The biochars produced by pyrolysis of corn cob at 400℃ and 600℃ were characterized and investigated as adsorbents for NH4＋ -N from an aqueous solution. The biochars were characterized through elemental analysis, Brunauer-Emmett-Teller-N2 surface area analysis, scanning electron microscopy, and Fourier transform infrared spectroscopy. Batch experiments were conducted to investigate the NH4＋ adsorption process of the corn cob biochars. The Freundlich isotherm model fitted the adsorption process better than the Langmuir and Dubinin-Radushkevich isotherm models. Moreover, the adsorption process was well described by a pseudo-second-order kinetic model. Results of thermodynamic analysis suggested that adsorption was a nonspontaneous exothermic process. Biochars produced at 400℃ had higher adsorption capacity than those produced at 600℃ because of the presence of polar functional groups with higher acidity. The exhausted biochar can be potentially used as soil conditioner, which can provide 6.37 kg NH4＋-N-t^-1 （N fertilizer per ton of biochar）.

Effect of ground corn cobs as a fiber source in total mixed ration on feed intake,milk yield and milk composition in tropical lactating crossbred Holstein cows

The aim of this study was to evaluate the effect of ground corn cobs(GCC) as a sole fiber source in total mixed ration(TMR) on feed intake, milk yield and milk composition in tropical lactating crossbred Holstein cows. Four multiparous crossbreds Holstein Friesian dairy cows with an initial body weight(BW) of 415.5 ± 26.20 kg were used in a 4 x 4 Latin square design. The dietary treatments of TMR contained a roughage-to-concentrate ratio of 40:60. The roughage source was used at different ratios of GCC to rice straw(RS) at 100:0, 82.5:17.5, 67.5:32.5, and 50:50 for TMR1 to TMR4, respectively. The results revealed significant improvements in intake of dry matter, protein,neutral detergent fiber(NDF)and metabolizable energy(ME) for TMR1 and TMR2(P < 0.05), while the digestibility of nutrients was not altered by the treatments(P > 0.05). Ground corn cobs was used for up to 100% of the total roughage without affecting milk production. Moreover, ruminal pH, temperature, ammonia-nitrogen(NH_3-N) and volatile fatty acid(VFA) concentrations were not impacted by the treatments(P> 0.05). However, milk yield was significantly different among the GCC:RS ratios(P < 0.05) and was the highest in TMR1 and TMR2(13.1 kg/d), while the milk compositions were not changed(P > 0.05). The results imply that using GCC as a whole roughage source significantly improved nutrients intake and milk yield in dairy cows raised in tropical areas.

发酵玉米芯多糖、还原糖含量近红外模型的建立

本实验旨在应用近红外光谱技术(NIRS)结合化学计量学法快速预测发酵玉米芯中多糖、还原糖含量,为定量检测发酵玉米芯多糖、还原糖含量提供理论依据以及为玉米芯深加工利用提供技术支持。以105份微生物发酵的玉米芯为供试材料,采用苯酚-硫酸法和DNS法分别测定多糖和还原糖含量。利用偏最小二乘法(PLS),通过不同预处方式和不同波长建立发酵玉米芯多糖、还原糖含量的近红外分析模型。结果表明:多糖模型采用标准正态变量变换(SNV)+1阶导数的方法对全谱图进行预处理的效果较好,优化后的模型决定系数(R2)、校正均方根误差(RMSEC)、校准标准差(SEC)分别为0.82、9.28、9.34,其相对分析误差(PRD)为2.37;还原糖模型采用1阶导数+标准正态变量变换(SNV)+去趋势化(Detrend)的方法对全谱图进行预处理的效果较好,优化后的模型决定系数(R2)、校正均方根误差(RMSEC)、校准标准差(SEC)分别为0.84、4.03、4.04,其相对分析误差(PRD)为2.48;预测集决定系数分别为0.85、0.88。本研究构建的NIRS模型校正和交互验证决定系数均较大,相对分析误差均大于2,说明模型预测性能较好,建立的模型有助于发酵玉米芯多糖、还原糖含量活性成分的筛选。

不同化学改性方法提高玉米芯骨料混凝土的性能

玉米芯具有较低的导热系数,可以作为天然的保温材料,用于混凝土砌块中。然而,由于玉米芯的多孔结构,导致玉米芯骨料混凝土的抗压强度偏低,亟需进行改性。为了推广玉米芯的规模化利用,该研究以玉米芯为原料改善混凝土砌块的性能,通过红外光谱、拉曼光谱和扫描电镜等测试手段,探讨了3种不同改性技术对玉米芯骨料混凝土水化产物化学键、分子结构、界面过渡区微观结构、抗压强度和导热系数的影响。结果表明:与环氧树脂改性相比,陶粒法改性和裹浆法改性不仅增加了玉米芯骨料混凝土界面过渡区的水化硅酸钙凝胶含量,同时也降低了界面过渡区的厚度,优化了混凝土砌块的微观结构、提高了混凝土砌块的抗压强度、降低了混凝土砌块的导热系数。其中,陶粒法改性技术的效果尤为明显。界面过渡区厚度水化硅酸钙特征峰由大到小顺序分别为陶粒法改性、裹浆法改性、环氧树脂改性。经过陶粒法改性、裹浆法改性和环氧树脂改性后,玉米芯骨料混凝土的界面过渡区分别为无明显界面过渡区、55~66 μm和93~101 μm之间。和未改性玉米芯骨料混凝土相比,掺30%陶粒法改性玉米芯骨料混凝土的抗压强度的导热系数分别降低了51.5%和32.2%。当掺入不超过15%的改性玉米芯骨料时,混凝土砌块满足国家标准GB/T8239-2014中对抗压强度的要求。为了改善玉米芯骨料混凝土砌块的综合性能,建议掺入不超过15%的陶粒法改性玉米芯骨料。研究结果为玉米芯在混凝土砌块中的大规模利用提供了依据,同时也为进一步改善混凝土砌块的相关性能提供了参考。

甜玉米芯多糖纳米乳微胶囊制备及释放

目的改善甜玉米芯多糖(SCP)大分子特性以及稳定性,促进SCP的肠道吸收。方法将SCP水溶液制备成油包水型(W/O)甜玉米芯多糖纳米乳液(SCP-NE),以复合蛋白为壁材制备成SCP-NE微胶囊,采用单因素试验、Box-Behnken设计和响应面法优化SCP-NE微胶囊制备工艺,以粒径分析、红外光谱分析、热重分析,对SCP-NE微胶囊物化性质进行研究,并进行体外模拟胃肠液释放研究。结果制备SCP-NE微胶囊最佳条件为麦芽糊精(MD)与大豆分离蛋白(SPI)的质量比为2∶3、芯壁比为1∶2、总体固形物含量为20%,此时包封率达到(87.6±1.3)%。体外模拟胃肠液释放结果表明,SCP-NE微胶囊在2 h的胃液消化中释放率为8.83%,在模拟肠液中1 h的释放量为62.87%。结论以MD和SPI作为壁材制备的SCP-NE微胶囊在胃肠液释放中具有良好的缓释性能。

玉米芯的不同处理方式对平菇生产的影响

采用熟料、发酵料、发酵短时高温3种方式处理的玉米芯进行平菇种植,分析3种处理方式对平菇生产的影响。结果表明:发酵短时高温料的菌丝生长速度最快,达到0.72 cm·d^(-1),熟料与发酵料菌丝生长速度差别不大。出菇前期,3种处理方式生产的平菇子实体农艺性状基本一致;出菇后期,熟料与发酵短时高温料生产的平菇子实体农艺性状均优于发酵料;熟料的玉米芯处理下平菇生物学效率最高,发酵短时高温的玉米芯处理下次之,发酵料的玉米芯处理下最低。

鲜食玉米收获机械发展阶段判定研究——基于收获效率与果穗损失视角

为促进鲜食玉米的高效低损收获,对鲜食玉米收获机械的发展进行阶段划分,并结合收获效率与果穗损失2个方面构建特征模式,基于模糊数学理论提出一种阶段划分方法,并结合4YZ-6型鲜食玉米收获机田间试验对该方法进行检验与可行性分析。结果表明该收获机收获效率与果穗损失率均低于2470型收获机,与判定的低效低损阶段相符。该阶段划即判定方法的提出,有助于加快我国鲜食玉米收获机械的高效低损发展,补全国内鲜食玉米机械化收获的短板问题。