2014, Vol.15, No.4

Carbon Letters 2023 KCI Impact Factor : 1.35 KCI-WoS Impact Factor : 4.82

pISSN : 1976-4251 / eISSN : 2233-4998
https://journal.kci.go.kr/carbon

The element carbon has been used as a source of energy for the past few hundred years,and now in this era of technology, carbon has played a significant and very prominent rolein almost all fields of science and technology. So as an honour to this marvellous element,we humans should know about its various forms of existence. In this review article, weshed light on all possible carbon-allotropes; similarities in their synthesis techniques and thestarting materials; their wide range of possible availability; and finally, future perspectivesand applications. A brief introduction is given on the types, structures, and shapes of the allotropesof carbon for a better understanding.

People have been concerned about mercury emissions for decades because of the extreme toxicity, persistence, and bioaccumulation of methyl Hg transformed from emitted Hg. This paper presents an overview of research related to mercury control technology and identifies areas requiring additional research and development. It critically reviews measured mercury emissions progress in the development of promising control technologies. This review provides useful information to scientists and engineers in this field.

In this work, thermal treatment accompanied with different acid treatments was applied toa commercial coal tar pitch (CTP) to obtain a spinnable precursor pitch for carbon fiber. In the case of thermal treatment only, a relatively high reaction temperature of between380°C and 400°C was required to obtain a softening point (SP) range of 220°C-260°C andmany meso-phase particles were created during the application of high reaction temperature. When nitric acid or sulfuric acid treatment was conducted before the thermal treatment, theprecursor pitch with a proper SP range could be obtained at reaction temperatures of 280°C-300°C, which were about 100°C lower than those for the case of thermal treatment only. With the acid treatments, the yield and SP of the precursor pitch increased dramatically andthe formation of meso-phase was suppressed due to the lower reaction temperatures. Sincethe precursor pitches with acid and thermal treatment were not spinnable due to the inhomogeneityof properties such as molecular weight distribution and viscosity, the CTP was mixedwith ethanol before the consecutive nitric acid and thermal treatments. The precursor pitcheswith ethanol, nitric acid, and thermal treatments were easily spinnable, and their spinningand carbon fiber properties were compared to those of air blowing and thermal treated CTP.