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3. Sustainable extraction of hazardous metals from crystal glass waste using biodegradable chelating agents

Author

Mutafela, R. N., Fei, Ye, Jani, Y., Dutta, Joydeep, Hogland, W., Mutafela, R. N., Fei, Ye, Jani, Y., Dutta, Joydeep, and Hogland, W.

Abstract

Extraction of hazardous metals from dumped crystal glass waste was investigated for site decontamination and resource recovery. Mechanically activated glass waste was leached with biodegradable chelating agents of ethylenediamine-N,N′-disuccinic acid (EDDS) and nitrilotriacetic acid (NTA), where the concentration and reaction time were determined by using Box–Wilson experimental design. Hazardous metals of lead (Pb), arsenic (As), antimony (Sb) and cadmium (Cd) with concentrations higher than regulatory limits were extracted wherein the extraction yield was found to vary Pb > Sb > As > Cd. Extraction was influenced more by type and concentration of chelator rather than by reaction time. A maximum of 64% of Pb could be extracted by EDDS while 42% using NTA. It is found that increase of chelator concentrations from 0.05 M to 1 M did not show improved metal extraction and the extraction improved with reaction time until 13 h. This study provides sustainable alternative for treating hazardous glass waste by mechanical activation followed by extraction using biodegradable chelator, instead of acid leaching. Graphical abstract: [Figure not available: see fulltext.]., QC 20221017

Published
2022
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4. Application of anaerobic digestion for biogas and methane production from fresh beach-cast biomass

Author

Burlakovs, J., Vincevica-Gaile, Z., Bisters, V., Hogland, William, Kriipsalu, M., Zekker, I., Setyobudi, R. H., Jani, Y., Anne, O., Burlakovs, J., Vincevica-Gaile, Z., Bisters, V., Hogland, William, Kriipsalu, M., Zekker, I., Setyobudi, R. H., Jani, Y., and Anne, O.

Abstract

In this research, biogas production potential from beach wrack collected in Riga Gulf (Ragaciems, Jaunķemeri, Bigauņciems) and in coastline of Sweden (Kalmar) was studied using an anaerobic digestion method. Selected beach wrack masses laying ashore and containing macroalgal biomass of common macroalgae types specific to the Baltic Sea were mixed for consolidated samples. Anoxic fermentation of untreated beach wrack was carried out in 16 bioreactors applying a single filling mode at 38 °C. The study revealed that by utilizing beach wrack accumulated ashore as a feedstock for anaerobic digestion methane can be utilized if pretreatment and conditioning of the samples are performed. The study was continued for selected brown algae containing biomass tested with three dewatering pretreatment methods: a) keeping in tap water for 24 hours; b) washing with running fresh water for one hour, and c) drying to relatively constant weight. The resulting methane outcome was compared with the data corresponding to raw brown algae. The study confirmed that washing of macroalgal biomass applied as pretreatment prior to anaerobic fermentation avoids inhibition of salts and promotes biomethane production.

Published
2022
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5. Efficient and low-energy mechanochemical extraction of lead from dumped crystal glass waste

Author

Mutafela, R. N., Ye, F., Jani, Y., Dutta, Joydeep, Hogland, W., Mutafela, R. N., Ye, F., Jani, Y., Dutta, Joydeep, and Hogland, W.

Abstract

Glass waste dumps from crystal glass production is an health issue due to the occurrence of antimony, arsenic, cadmium and lead in crystal glass. Recovery of those elements could both decrease pollution and recycle metals in the circular economy. Pyrometallurgy is a potential recovery method, yet limited by high energy consumption. Here we tested a lower-energy alternative in which glass is mechanically activated in a ball mill and leached with nitric acid. Results show that mechanical activation destabilised the glass structure and resulted in 78% lead extraction during leaching at 95 °C. Temperature had the most significant effect on extraction, whereas acid concentration, from 0.5 to 3 M, and leaching time, from 0.5 to 12 h, had insignificant effects. In each experiment, 75% of the final extracted amount was achieved within 30 min. The study demonstrates potential for lead extraction from glass waste at lower acid concentration, shorter leaching time and lower temperature, of 95 °C, than traditional pyrometallurgical extraction, typically operating at 1100 °C., QC 20210318

Published
2021
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21. Metamaterial Concentrator for Thermal Energy Harvester.

Author

Hendroko Setyobudi, R., Danang Birowosuto, M., Kala Mahaswa, R., Jani, Y., Vincēviča-Gaile, Z., Nichita Kaikatui, Rapha, Putra Andika, Adik, Letsoin, Vinsenius, Mangera, Paulus, Hardiantono, Damis, Adhi Nugroho, Yogo, Susanto, Herry, and Wibowo, Haryo

Published
2020
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50. Pengaruh Kepemimpinan Spiritual Terhadap Kinerja Karyawan Pada PT. Ciputra International Proyek City of Blessing Citraland Manado

Author

Rondonuwu, Jani Y., Areros, William A., and Sambul, Sofia A. P.

Abstract

This study aims to see whether there is influence between spiritual leadership on employee performance, especially at the company PT. Ciputra International Project City Of Blessing Citraland Manado. where the respondents in the company amounted to 49 people, who are employees of the company. and in this study, researchers get a singnifikan result where there is a strong influence between spiritual leadership and employee performance. this study is excellent as a recommendation to the company to maintain the values of spiritual leadership for its employees to be applied, especially for employee. According to (Chopra, 2002) leadership and also spiritrualitas have a huge influence on the Organization as a whole. This research use descriptive quantitative research methods by using the correlation coefficient analysis approach. Then, the results of this research were obtained that support of existing theories, namely the spiritual leadership of the significant effect on the performance of employees. In conclusion, based on the results of research that the degree of spiritual leadership influence on performance of employees at PT. Ciputra International Project of the City of Manado Citraland Blessing are included in the category is strong where it is demonstrated by the results of the correlation coefficient or r = 0.798 or 79.8%. and advice to researchers next expected to be able to improve this independent variable research more deeply, through the selection of the place of proper research and research methods that are different or the same.Keywords: Spiritual Leadership, Employee Performance

Published
2017

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