Review on the physicochemical treatments of rice husk for production of advanced materials

Production of activated carbon from bagasse and rice husk by a single-stage chemical activation method at low retention times.

Investigation of thermodynamic parameters in the pyrolysis conversion of biomass and manure to biochars using thermogravimetric analysis.

All chapters of the previous edition [see HbA 37, 2103] have been completely rewritten to cover the rapid increase in research in this area. The number of literature citations have been reduced by referring to recent review articles and the book aims at a comprehensive and critical rather than encyclopaedic summary of the data of environmental chemistry. The 1st 4 chapters deal with air, water, rocks and soils; the cycling of C, N, H, O2 and S in the biosphere are covered in 1 chapter and the elemental Other CABI sites 

Environmental Chemistry of the Elements

The present overview is intended to point the readers' attention to the important subject of calcium orthophosphates. This type of materials is of special significance for human beings, because they represent the inorganic part of major normal (bones, teeth and antlers) and pathological (i.e., those appearing due to various diseases) calcified tissues of mammals. For example, atherosclerosis results in blood vessel blockage caused by a solid composite of cholesterol with calcium orthophosphates, while dental caries and osteoporosis mean a partial decalcification of teeth and bones, respectively, that results in replacement of a less soluble and harder biological apatite by more soluble and softer calcium hydrogenphosphates. Therefore, the processes of both normal and pathological calcifications are just an in vivo crystallization of calcium orthophosphates. Similarly, dental caries and osteoporosis might be considered an in vivo dissolution of calcium orthophosphates. Thus, calcium orthophosphates hold a great significance for humankind, and in this paper, an overview on the current knowledge on this subject is provided.

https://www.tandfonline.com/doi/pdf/10.4161/biom.18790

Calcium orthophosphates: Occurrence, properties, biomineralization, pathological calcification and biomimetic applications

Non-isothermal kinetics of pyrolysis of rice husk

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.

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

Bioactive fluorapatite-containing glass ceramics

The synthesis of zeolite with valuable properties is a serious task, requiring numerous laboratory studies. Zeolite NaX (also called zeolite X, NaX, Linde X and molecular sieve 13X) is an analogue of the natural zeolite faujasite. The aim of the present paper is to investigate the most important stage of synthetic zeolite production - the process of its granulation. The granulation is obtained on the basis of three mechanisms involving different types of granulators or installations. The subject matter of the work is zeolite granulate of type Zeolite NaX with or without a binding substance. For this purpose, a laboratory installation of „fluidized bed“ was designed and manufactured. The method of „fluidized bed“ is a very effective method by which the synthesis takes place in the micro-volumes of the material. The granules obtained have an average particle size within the range of about 1 to 4 mm and also good mechanical strength.

A study on the synthesis and structure of zeolite nax

The effective utilization of waste rice husk requires detailed studies on the kinetics and mechanism of their thermal and chemical treatment. The present work is a comparative study on the thermo-chemical and kinetic characteristics of thermal degradation of raw and treated with NaOH rice husk. The optimal conditions for extraction of SiO2 from rice husk in the form of Na2SiO3 were determined using thermal analysis(TA),scanningelectronmicroscope(SEM)andelementalanalysis.Theexperimentswerecarried out under conditions of non-isothermal heating in air and nitrogen atmosphere. Using different kinetic models, the values of the effective kinetic parameters, characterizing the destruction process were determined.

Irena Markovska

Papers

Non-isothermal kinetics of pyrolysis of rice husk

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

Bioactive fluorapatite-containing glass ceramics

A study on the synthesis and structure of zeolite nax

Study on the Thermochemical and Kinetic Characteristics of Alkali Treated Rice Husk