• Asian-Australasian Journal of Animal Sciences
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• v.7 no.4
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• pp.481-486
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• 1994

The effect of neutralization of urea-treated rice straw with sulfuric acid was investigated. Long-cut (15-20 cm) and short-cut (2-3 cm) rice straw were treated with 6% urea for 21 days, and the treated straw was mixed with an acid-molasses solution to neutralize free ammonia and kept airtightly in a plastic bag for 24 hours. The neutralized and non-neutralized straw were dried and subjected to chemical analysis and in vitro dry matter (DM) digestibility determination. The in vitro DM digestibility as well as crude protein (CP) content were remarkably improved by neutralization. Short-cutting of the straw before treatment gave a better result than the long-cut samples. Neutralization with sulfuric acid also affected the chemical composition and increased sulfur content of samples. The CP thus fixed by neutralization was proven to be kept stable for 3 months, and in vitro DM digestibility was not affected by the storing period.

• Journal of The Korean Society of Grassland and Forage Science
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• v.11 no.1
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• pp.43-52
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• 1991

The overall objective of this research was to evaluate the effects of spraying sulfuric acid solution, and adding corn meal or molasses to reed canarygrass silage on digestibility of dry matter (DM) and fibrous components in ruminant. DM content of molasses or corn meal treated silages were higher than control. Whereas, sulfuric acid treated silage showed lower DM content compared with untreated control. Acid detergent fiber content was similar among treatments, but neutral detergent fiber (NDF) and hemicellulose concentration were higher in treated silages than those of control. Organic acids content were also increased in treated silages. In contrast, silage pH were lower in treated silages. Treated silages increased both rate and extent of DM and NDF in situ digestibility compared to control at all incubation times. Especially, 7 % molasses and 0.4 % sulfuric acid treated silages increased DM and NDF digestibility significantly after 12 hours of incubation compared with control. In nitro DM and NDF digestibility showed similar trend to in situ incubation. Also treated silages(mo1asses or sulfuric acid treated) incubated in situ had higher particle-associated carboxymethylcellulase activity throughout the incubation except 72 hours.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.54 no.3
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• pp.320-326
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• 2009

The crops showing hard seed character have high seed viability after seed storage for long period. The low germination rate due to hard seed coat, however, cause a problem of low seedling establishment in field condition. Three legumes used in the experiment, lablab bean (Dolichos lablab L.), asparagus bean (Vigna sesquipedalis L. Fruwirth), and soybean (Glycine max L. Merr.), showed low germination rate (26, 17, and 5%, respectively) due to thick and hard seed coat. In this study artificial treatment for breaking dormancy was tested in hard seeds. The effect of proper treatment was various depending on species. The germination rate of lablab bean was highly improved up to 94% by soaking into water for 24 hours. In the case of asparagus bean, the rate was increased up to 90% by soaking for eight hours near boiling water until it cools. The germination rate of small hard seed soybean was increase to 96% by soaking into concentrated sulfuric acid for 10 minutes. Ultrastructural change revealed by scanning electron microscope (SEM) reflects that the structure of micropyle was changed and water uptake was facilitated with all treatments tested in the experiment. Especially, sulfuric acid treatment resulted in the degradation of micropylar tissue. These results demonstrate that the artificial treatment including sulfuric acid and (hot) water soaking treatment for promoting water uptake can be applied to improve seed germination in legume seed with thick and hard seed coat.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.11
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• pp.2059-2065
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• 2000

The purpose of this study is to improve coagulation efficiency by pre-treatment of high pH water using sulfuric acid. The common reason of pH increasing at down stream of Nakdong river is water blooming. The pH go above 9.0 during water blooming periods. The higher pH water demands more coagulant and pre-chlorine dosage than lower pH water for better coagulation condition. The DOC, THMFP, UV-254 after coagulation with the same coagulant dosage by pre-treatment from pH 9.2 down to 8.1 with sulfuric acid are 1.84mg/L, $51{\mu}g/L$ and $0.032cm^{-1}$, by pretreatment of chlorine are 2.09mg/L, $78{\mu}g/L$ and $0.030cm^{-1}$, by pre-treatment of sulfuric acid and chlorine are 2.14mg/L, $72{\mu}g/L$ and $0.031cm^{-1}$ respectively. Pretreatment with sulfuric acid can improve water quality and reduce coagulant demand.

• Journal of the Korean institute of surface engineering
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• v.52 no.5
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• pp.275-281
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• 2019

Anodization is widely used to enhance the properties of aluminum, such as hardness, electric resistance, abrasion resistance, corrosion resistance etc. But these properties can be enhanced with additional process. According to the partial crystallization of oxide layer with post heat treatment, enhanced hardness can be expected with partial crystallization. In this study, post heat treatments were applied to the anodized aluminum alloys of Al6061 to achieve the partial crystallization, and crystallizations were evaluated with the reduced breakdown voltages. Interestingly, remarkable enhanced hardness (21~29%), abrasion resistance (26~62%), and reduced breakdown voltage (24~44%) were observed for the sulfuric acid anodized samples when we annealed the anodized samples with 1hour post heat treatment at $360^{\circ}C$. For the Al5052 alloys, a lot of cracks were observed when we applied the post heat treatment.

• Carbon letters
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• v.3 no.4
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• pp.187-191
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• 2002

In the present research, we prepared the activated carbon (AC) sorbents to remove gas-phase mercury. The mercury adsorption of virgin AC, chemically treated AC and fly ash was performed. Sulfur impregnated and sulfuric acid impregnated ACs were used as the chemically treated ACs. A simulated flue gas was made of SOx, NOx and mercury vapor in nitrogen balance. A reduced mercury adsorption capacity was obtained with the simulated gas as compared with that containing only mercury vapor in nitrogen. With the simulated gas, the sulfuric acid treated AC showed the highest performance, but it might have the problem of corrosion due to the emission of sulfuric acid. It was also found that the high sulfur impregnated AC also released a portion of sulfur at $140^{\circ}C$. Thus, it was concluded that the low sulfur impregnated AC was suitable for the treatment of flue gas in terms of stability and efficiency.

• Textile Coloration and Finishing
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• v.7 no.2
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• pp.9-16
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• 1995

When alkaline waste water of PET fabric is treated with sulfuric acid, undegradable material, crude TPA sludge is generated, so that treatment has a serious problem. The result of DMT synthesis using crude TPA sludge generated from PET alkaline waste water were as follows: 1. When crude TPA generated from alkaline waste water is reactioned with methanol under catalyst of sulfuric acid, pure DMT can be obtained. 2. In DMT synthesis from crude TPA, addition of copper sulfate can increase yield, and increasing the amount of sulfuric acid can shorten reaction time.

• 한국신재생에너지학회:학술대회논문집
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• 2006.11a
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• pp.541-543
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• 2006

The feasibility of biodiesel production from soapstock by acid catalyst was tested. The water content of soapstock was more than 40%. Before the esterification of soapstock, the pre-treatment of soapstock was conducted adding potassium hydroxide and sulfuric acid. The pre-treated soapstock contained 99.6wt% of free fatty acid. When the free fatty acid was esterified with methanol, the fatty acid methyl ester content became 91.7wt% under the solid acid catalyst, Amberlyst-15. When this biodiesel was distilled the methyl ester content was 98.1wt% which satisfied the biodiesel Standard. Amberlyst-15 could be recovered easily because it was the soliid catalyst. When sulfuric acid was used as the acid catalyst, the fatty acid methyl ester content was 91.0wt%. From the results, it was possible to produce biodiesel efficiently from soapstock after pre-treatment. Because soapstock is very cheap, it will become good feedstock for biodiesel product ion.

• Journal of the Korea Organic Resources Recycling Association
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• v.19 no.3
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• pp.79-89
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• 2011

The wasted corn stalk from Gangwon province is composed of 44.6 % glucan, 19.0 % xylan, 23.8 % lignin, 4.5 % ash and 8.1 % others. Statistical analysis, full factorial design, revealed that temperature was the most influential factor in the dilute sulfuric acid pretreatment and that the influence of temperature on xylose yield was 3.5 and 3.2 times higher than those of treatment time and acid concentration, respectively. Temperature was also the most influential factor for glucose yield in the pretreatment but it was less than 5 % throughout the pretreatment. Although minor sugar yield was observed when microwave or ultrasonication was solely introduced as a pretreatment method, the complex method incorporating microwave or ultrasonication into dilute sulfuric acid pretreatment enhanced sugar yield significantly. In particular, xylose yield was doubled when microwave and dilute sulfuric acid treatment was sequentially applied. The optimization of pretreatment and enzymatic hydrolysis as well as the investigation on the complex pretreatment in detail are left for further study.

• Resources Recycling
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• v.20 no.1
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• pp.61-68
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• 2011

Impurity removal from metallurgical grade silicon by acid washing at $50^{\circ}C$ was investigated by employing sulfuric, nitric acid and the mixture of hydrochloric and hydrofluoric acid. Acid washing treatment had no effect on the removal of boron and the concentration of this clement after treatment was rather increased. In our experimental range, the removal percentage of phosphorus was 60%. In the acid washing with sulfuric and nitric acid, the removal percentage of major impurities was below 50%, which indicates that refining effect was not great with these acids. Acid washing with the mixture of hydrochloric and hydrofluoric acid led to removal percentage of higher than 90%. Data on the purity of silicon after acid washing at various conditions are reported.