Difficulties in the production of lignin from rice straw because of high silica content in the recovered lignin reduce its recovery yield and applications as bio-fuel and aromatic chemicals. Therefore, the objective of this study is to develop a novel method to reduce the silica content in lignin from rice straw more effectively and selectively. The method is established by monitoring the precipitation behavior as well as the chemical structure of precipitate by single-stage acidification at different pH values of black liquor collected from the alkaline treatment of rice straw. The result illustrates the significant influence of pH on the physical and chemical properties of the precipitate and the supernatant. The simple two-step acidification of the black liquor at pilot-scale by sulfuric acid 20w/v% is applied to recover lignin at pH 9 and pH 3 and gives a percentage of silica removal as high as 94.38%. Following the developed process, the high-quality lignin could be produced from abundant rice straw at the industrial-scale.

https://biblio.ugent.be/publication/8683603/file/8683604.pdf

The novel method to reduce the silica content in lignin recovered from black liquor originating from rice straw.

Pyrolyzed Pencil Graphite Coated Cellulose Paper as an Interlayer: An Effective Approach for High-Performance Lithium-Sulfur Battery

A chemical method to synthesize amorphous silica nanoparticles from the incinerated paddy straw has been introduced. The synthesis was conducted through the hydrolysis by alkaline-acidic treatments...

Production and characterization of silica nanoparticles from fly ash: conversion of agro-waste into resource.

Abstract There is increased interest in the terrestrial silicon cycle in the last decades as its different compounds and species have large implications for ecosystem performance in terms of soil nutrient and water availability, ecosystem productivity as well as ecological aspects such as plant–microbe and plant-animal feedbacks. The currently existing analytical methods are limited. Fourier-transform infrared spectroscopy (FTIR) analysis is suggested being a promising tool to differentiate between the different Si species. We report here on the differentiation of varying Si-species/Si-binding (in synthetic material) using FTIR-analyses. Therefore, we collected FTIR-spectra of five different amorphous silica, Ca-silicate, sodium silicate (all particulate), a water-soluble fraction of amorphous silica and soil affected by volcanic activity and compared their spectra with existing data. A decrease of the internal order of the materials analyzed was indicated by peak broadening of the Si–O–Si absorption band. Peak shifts at this absorption band were induced by larger ions incorporated in the Si–O–Si network. Additionally, short-range ordered aluminosilicates (SROAS) have specific IR absorption bands such as the Si–O–Al band. Hence, SROAS and Si phases containing other ions can be distinguished from pure amorphous Si species using FTIR-analyses. 

/pdf/comparing-amorphous-silica-short-range-ordered-silicates-and-mt25aaax.pdf

Comparing amorphous silica, short-range-ordered silicates and silicic acid species by FTIR

Modern trends in the development of the oil and gas infrastructure of the Russian Far East are considered. The main threats in the operation of oil and gas pipelines are described. The technology of complex protection of pipeline surfaces is proposed. Protection of the inner surface is achieved through the use of silicate enamel coatings, protection of the external surface – through the use of foam glass. On the basis of local silicate raw materials the technology of the described materials is developed, and their main properties are determined. Recommendations on the application of the developed technology for the protection of pipelines are given.

Complex Protection of Pipelines Using Silicate Materials Based on Local Raw Materials of the Far East

Contents of silica and extractive substances in rice straw depending on rice varieties were investigated. The samples of amorphous silica were prepared, their microelement composition and morphology were investigated, and the values of true and bulk density were estimated. The porous structure of the samples was studied by the Brunauer-Emmett-Teller (BET) method and by water vapour sorption; the specific surface values, as well as the pore diameter and volume, were also determined. Sorption properties of the SiO2 surface were analyzed on a sample of Mn2+-ions and the organic dyes brilliant green and methylene blue.

https://ojs.cnr.ncsu.edu/index.php/BioRes/article/download/BioRes_10_2_3713_Zemnukhova_Dependence_Porosity_Rice_Straw/3525

Dependence of Porosity of Amorphous Silicon Dioxide Prepared from Rice Straw on Plant Variety

Рассмотрены возможности применения композитного катализатора на основе углеродного волокна с железом/оксидом железа для гетерогенного жидкофазного окисления фенола пероксидом водорода. Обсуждаются вопросы каталитического разложения пероксида водорода до реакционно активных радикалов в присутствии гетерогенных катализаторов – активированного угля и композитов на его основе, содержащих металл/оксид металла. Деградация и удаление фенола происходит за счет реакции с гидроксил-радикалами, которые образуются из пероксида водорода в присутствии ионов Fe на поверхности катализатора и в растворе. Исследовано влияние на эффективность удаления фенола таких факторов, как величина рН и соотношение фенол:пероксид водорода при исходной концентрации фенола, равной 0,182·10 моль/л. Во всех опытах проводился анализ раствора на УФ-спектрофотометре через определенные интервалы времени при контролируемых значениях параметров. Степень деградации фенола (%) определялась как отношение изменения концентраций в момент определения к исходной величине. Показана эффективность деградации фенола в присутствии гетерогенного катализатора углеродное волокно/(железо/оксид железа), и обнаружено, что существует оптимальное сочетание рН и мольного соотношения фенол:пероксид водорода, при которых происходит более полное удаление фенола из воды. Так, при рН 4 и соотношении фенол:пероксид водорода 1:6 степень деградации органического загрязнителя достигает 88%. В этих условиях композит УВ/(Fe, оксид железа) является эффективным гетерогенным катализатором деградации и удаления фенола из воды.

/pdf/kataliticheskoe-zhidkofaznoe-okislenie-fenola-v-vodnykh-45qigqi4pl.pdf

Andrey P. Artemyanov

Papers

Dependence of Porosity of Amorphous Silicon Dioxide Prepared from Rice Straw on Plant Variety

Каталитическое жидкофазное окисление фенола в водных средах с использованием катализатора углеродное волокно/(железо, оксид железа)

New composite materials based on activated carbon fibers with specific adsorption and catalytic properties