KOH activated pine tree needle leaves biochar as effective sorbent for VOCs in water

Theoneste, Nshirirungu,Kim, Moon Hyun,Solis, Kurt Louis,Park, Minoh,Hong, Yongseok Techno Press 2018 Membrane Water Treatment Vol.9 No.5

The removal of volatile organic compounds (VOCs) from water using KOH-activated pine tree needle leaves biochar is considered a cost effective and efficient process. In this study, pine tree needle leaves were mixed with 0, 50, 100 and 200% (KOH weight/feedstock weight) of KOH, respectively. Then, the mixture was pyrolyzed at <TEX>$500^{\circ}C$</TEX> for 6 hrs. The adsorption characteristics of 10 VOCs to the biochar were tested. The results indicated that the removal efficiency of the KOH activated biochar was highest in 100% KOH-biochar. The VOC removal efficiencies of 50% and 200% KOH activated biochar were similar and the 0% KOH activated biochar showed the lowest VOC removal. The FTIR results showed that increasing the amount of KOH seemed to enhance the formation of various functional groups, such as -OH, -C=C, -O. The adsorption strength of 10 VOCs to the KOH activated biochar seemed to be increasing by the increase of the solubility of VOCs. This may suggest that the adsorption is taking place in hydrophilic sites of the biochar surface. The KOH activated pine tree needle leaves biochar can be an effective sorbent for VOCs removal in water and 100% KOH mixing seemed to provide better sorption capacity.

Recycling of valuable elements from spent Li-ion batteries via hydrothermal process

Theoneste Nshizirungu,Masud Rana,Jeong-Hun Park 대한환경공학회 2020 대한환경공학회 학술발표논문집 Vol.2020 No.11

Impact of Urbanization on Land use and Land Cover Changes in Growing Cities of Rwanda

Theoneste Bimenyimana,Eric Derrick Bugenimana,Eliezel Habineza,Magreth S. Bushesha,ALI MOHAMMOD 대한환경공학회 2022 대한환경공학회지 Vol.44 No.8

The effect of urbanization on environmental justice in Rwanda from 1999 to 2019 is examined in this research. Specifically, the research sought to document changes in land use and land cover in the study region from 1999 to 2019, to analyze the environmental consequences of urban growth in Rwanda. Land use/land cover patterns were identified and modelled using remotely sensed data. The results show that, in the majority of instances, built-up areas have increased at 15 to20% , whereas forests, vegetation and water bodies have decreased 49% in Nyagatare city. It has been observed that urbanization is out of step with the natural urban environment, resulting in soil erosion, violent winds, flooding, and landslides, all of which are associated with the failure of environmental justice. 64 people died and 178 injured in 5 years, settlement destruction, flooding occurrences, infrastructure damage, loss of natural habitat, and agricultural loss are all associated with urban development, especially uncontrolled settlements in metropolitan settings. The research suggests that current households in high-risk zones be moved to other zones and the government should strengthen its greening city strategy and raise public understanding of environmental issues.

Diluted formic acid (DFA) assisted leaching of valuable metals (Li and Co) from spent LiCoO₂ cathode material under hydrothermal conditions

( Theoneste Nshizirungu ),( Masud Rana ),( Md Ishtiaq Hossain Khan ),( Young Tae Jo ),( Jeong-hun Park ) 한국폐기물자원순환학회 2022 ISSE 초록집 Vol.2022 No.-

Inadequate and inappropriate recycling technologies for e-waste have led to many environmental and economic problems, including the loss of strategic metals from spent cathode materials such as LiCoO₂, high energy consumption, and the generation of hazardous materials. In this study, we proposed a novel and environmentally benign process for leaching, separating, and recovering strategic metals such as lithium (Li) and cobalt (Co) from spent lithium-ion batteries (LIBs) over hydrothermal reaction conditions assisted by dilute formic acid (DFA). The effects of experimental parameters such as (H₂O: HCOOH) ratio (v/v), temperature, reaction time, and liquid-solid ratio on the extraction performance of Li and Co have been carefully evaluated. The findings revealed that DFA successfully leaches Li and Co from the spent LiCoO₂ cathode materials of Li-ion batteries without any assistance from reducing reagents. The solid materials were characterized by XRD, XPS, FT-IR, and SEM-EDS analyses. However, the leaching liquor was analyzed by ICP-OES. At 220°C, a reaction time of 25 min, an H₂O: HCOOH ratio (v/v,) of 78:12, and a liquid-solid ratio of 25 mL/g, 99.89% for Li and 99.56% for Co were effectively leached from the spent LiCoO₂ powder. Further, the activation energy for Li was 24.15KJ/mol, while that for Co was 31KJ/mol. Finally, Co₂O₃ nanoparticles and Li₂CO₃ were successfully recovered from the leaching liquor by the precipitation and calcination methods after the separation steps. Therefore, this process could be an alternative method due to its low energy consumption, ease of use, and being environmentally friendly.

Subcritical water leaching of valuable and hazardous metals (Ni, Co, and Cd) from waste Ni-Cd batteries using ferric chloride hexahydrate (FeCl_3.6H₂O)

( Md Ishtiaq Hossain Khan ),( Masud Rana ),( Theoneste Nshizirungu ),( Jeong Hun Park ) 한국폐기물자원순환학회 2022 ISSE 초록집 Vol.2022 No.-

Many valuable metals may be found in waste Ni-Cd batteries. The leaching of valuable metals from waste Ni-Cd batteries has attracted tremendous attention in recent years. In spite of this, it remains difficult to develop a sustainable and efficient method. The purpose of this study was to investigate an efficient, convenient, and innovative way to recycle valuable metals from waste Ni-Cd batteries. Heavy metals from Ni-Cd batteries were leached in subcritical water using ferric chloride hexahydrate (FeCl₃.6H₂O). By releasing HCl in subcritical water, ferric chloride hexahydrate (FeCl₃.6H₂O) accelerates metals' leaching performance. Ni, Cd, and Co leaching efficiencies were also extensively studied using reaction parameters, such as temperature, time, solid-to-liquid ratio, and Ni-Cd powder-to-FeCl₃.6H₂O mass ratio. FT-IR, XRD, SEM-EDS, and XPS analyses were carried out on solid residues obtained after subcritical water leaching experiments. The leachate was analyzed by ICP-OES. In the optimized conditions, Ni, Cd, and Co leached with almost (93, 95, and 100) % efficiency; at 300°C, 120 minutes, 15g/L solids/liquids ratio, and 1:3 Ni-Cd-to-FeCl₃.6H₂O mass ratios. For the recovery of valuable metals from waste Ni-Cd batteries, the subcritical water leaching has been found to be efficient, environmentally friendly, and sustainable method.

Ultrasound-assisted leaching of spent Ni-Cd batteries via Glycine

( Md Ishtiaq Hossain Khan ),( Masud Rana ),( Theoneste Nshizirungu ),( Young Tae Jo ),( Jeong-hun Park ) 한국폐기물자원순환학회 2022 한국폐기물자원순환학회 심포지움 Vol.2022 No.1

Ultrasound-assisted leaching of spent Ni-Cd batteries via Glycine

( Md Ishtiaq Hossain Khan ),( Masud Rana ),( Theoneste Nshizirungu ),( Young Tae Jo ),( Jeong-hun Park ) 한국폐기물자원순환학회 2022 한국폐기물자원순환학회 춘계학술발표논문집 Vol.2022 No.-

소나무 나뭇잎에서 추출한 황 함유 Biochar에 의한 수은 제거

커트루이스솔리스 ( Kurt Louis Solis ),테오네스테 ( Theoneste Nshizirungu ),박민오 ( Park Min Oh ),홍용석 ( Yongseokhong ) 한국물환경학회(구 한국수질보전학회) 2018 한국물환경학회·대한상하수도학회 공동 춘계학술발표회 Vol.2018 No.-

비소 및 수은 등으로 복합오염된 폐 광산 주변 토양 위해성평가

박성재(Seong-Jae Park),김준(Jun Kim),조영태(Young Tae Jo),신동(Dong Shin),테오네스테(Theoneste Nshizirungu),문덕현(Deok Hyun Moon),지원현(Won Hyun Ji),고주인(Ju In Ko),박정훈(Jeong-Hun Park) 대한환경공학회 2020 대한환경공학회지 Vol.42 No.2

목적 : 국내 휴 · 폐광산은 약 2,000여개 존재하고 있다. 이 중 대부분이 적절한 환경오염의 방지시설 없이 광미, 폐석, 갱내수 등, 광산폐기물의 방치로 인한 여러 문제점이 제기되어왔다. 광산폐기물은 다양한 유해 금속 및 비금속 물질을 고농도로 함유하고 있다. 또한 인근 토양과 하천, 지하수 등의 중금속 오염원이 될 수 있으며, 중금속은 생태계에 오랜 기간 존재하여 농작물 및 식수를 통한 인근 지역 주민들의 체내로 유입될 가능성이 있다. 따라서 본 연구에서는 토양 내 중금속 오염에 대한 인체 위해성 평가를 실시하였다. 방법 : 564개 샘플의 중금속농도를 분석하였으며, 토양오염물질에 대한 위해성 평가는 유해성 확인(Hazard identification), 노출평가(Exposure assessment), 독성평가(Toxicity assessment), 위해도 결정(Risk characterization) 순서로 진행하였다. 결과 및 토의 : 185지점이 비소의 토양오염우려기준을 초과하는 것으로 나타났으며, 구리 1지점, 납 1지점, 아연 7지점, 수은 3지점이 초과하는 것으로 조사되었다. 토양 접촉은 성인과 어린이에게 가장 큰 영향을 미쳤으며, 농작물섭취, 토양섭취, 토양 흡입 순으로 나타났다. 성인과 어린이의 발암 위해도 모두 토양 접촉, 농작물 섭취, 토양섭취, 비산먼지흡입 순서로 기여율을 보였다. 성인 비발암 기여도의 경우 농작물섭취 > 토양섭취 > 토양접촉 > 실외휘발물질흡입 > 지하수섭취 > 비산먼지흡입 나타났다. 어린이의 경우 토양섭취 > 농작물섭취 > 토양접촉 > 실외휘발물질흡입 > 지하수섭취 > 비산먼지흡입 순으로 조사되었다. 결론 : 해당 부지의 발암정화목표치는 성인과 어린이의 농도를 고려하여 비소 농도를 7.17 mg/kg 수준으로 정화하여야 하는 것으로 나타났다. 그러나 비소의 피부흡수발암계수(SFabs)를 USEPA에서 제시한 방법을 활용한 경우 발암정화목표치가 20.08 mg/kg이 산출되어 국내 위해성 평가 인자에 대한 추가적인 연구가 요구된다. Objectives : In Korea, about 2,000 abandoned mine area has been polluted by harmful waste such as mine tailing, waste rock and acid mine drain without prevention facility. Mine waste contains high concentrations of various hazardous metallic and nonmetallic materials. Also, it can be a source of pollution for nearby soil, rivers, and ground water. Heavy metals may exist in ecosystems for a long time and may be taken by the residents through crops and drinking water. In this study, human risk assessment for heavy metal contamination was carried out. Methods : About the 564 soil samples were analyzed for heavy metal. The risk assessment of polluted soils was carried out in accordance with guideline of Korea Soil Environment Conservation Act. It was implied with hazard identification, exposure assessment, toxicity assessment, and risk characterization. Results and Discussion : The number of exceed sites for the worried level of soil concentration were 185 for As, 3 for Hg, 7 for Zn, 1 for Pb, 1 for Cu. Soil contact was the biggest impact on adults and children for carcinogenic risk followed by crop intake, soil intake, and soil inhalation. Non-carcinogenic risk for adults, were in order of crop intake > soil intake > soil contact > outdoor air inhalation (volatilization) > ground water intake and soil inhalation. For children, it was in the order of soil intake > crop intake > soil contact > outdoor air inhalation (volatilization) > ground water intake > soil inhalation. Conclusion : The carcinogenic purification target concentration for the site was determined to be 7.17 mg / kg level of arsenic, considering adult and child concentrations. However, carcinogenic purification target concentration by arsenic dermal absorption carcinogenic coefficients (SFabs) of USEPA method was 20.08 mg/kg, therefore requiring research for domestic risk assessment factor.

Red cell distribution width and preeclampsia: a systematic review and meta-analysis

Ishag Adam,Theonest K. Mutabingwa,Elfatih M. Malik 대한고혈압학회 2019 Clinical Hypertension Vol.25 No.4

Background: Preeclampsia is a serious pregnancy-related disease which may lead to adverse health effects to the mother and fetus. Besides many publications on the association of red cell distribution width (RDW) and preeclampsia, there has been no published meta-analysis. This necessitated the present systemic review and metanalysis to assess the RDW in relation to preeclampsia. Methods: Preferred Reporting Items for Systematic Reviews and Meta-Analyses guideline was followed. Relevant published studies were searched in PubMed, Cochrane library, Google scholar, Scopus, Embase and CINAHL using the term “Preeclampsia OR eclampsia AND red cell distribution width OR red blood cells). Modified Newcastle – Ottawa quality assessment scale was used for critical appraisal of retrieved studies. Pooled Meta logistic regression was computed using OpenMeta Analyst software. Subgroup and meta-regression methods were performed to analyse the heterogeneity. Results: Eleven case control studies were included in the met-analyses with a total of 951 cases (preeclampsia) and 2024 controls. The mean (SD) of the RDW level was significantly higher in women with preeclampsia compared to controls [15.10 (2.48) % vs. 14.26(1.71) %, P < 0.001]. The mean difference was 0.85, 95% CI = 0.26–1.43. Due to a high heterogeneity (I2 = 90.45, P < 0.001), the continuous random effect model was used. Eight studies compared RDW level in the mild (N = 360) with severe cases (N = 354) of preeclampsia. The RDW level was significantly higher in women with severe preeclampsia compared to those with mild preeclampsia [15.37 (2.48) % vs. 14.037(1.79) %, P < 0.001]. The mean difference was 1.07, 95% CI = 0.45–1.70. Since there is a high heterogeneity [I2 = 76.67, P < 0.001], the continuous random effect model was used. Through the met-regression model, except for the region of the study (P < 0.001), none of investigated variables (age, parity, quality of the study) was significantly associated with the investigated heterogeneity. The outliers (3studies) were removed to reduce the heterogeneity. The pooled meta-analysis of the remaining 8 studies showed a significant difference in the RDW between preeclamptic women compared with the controls. The mean difference was 0.93, 95% CI = 0.56–1.31, P < 0.001. Because of heterogeneity [I2 = 69.6, P = 0.002], the continuous random effect model was used. Conclusion: RDW level was significantly higher in women with preeclampsia compared to controls. Similarly, women with severe preeclampsia had significantly higher RDW than those with the mild form.