A review of semiconductor wastewater treatment processes: Current status, challenges, and future trends

Sim, Jeonghoo; Lee, Jonghun; Rho, Hojung; Park, Kwang-Duck; Choi, Youngkwon; Kim, Deokhwan; Kim, Hyeonbin; Woo, Yun Chul

doi:10.1016/j.jclepro.2023.139570

Cited by 21 publications

(8 citation statements)

References 78 publications

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“…In this study, the synthetic wastewater used was formulated to replicate the typical composition of semiconductor hydrofluoric acid wastewater [20]. The synthetic wastewater was prepared with the following characteristics: pH: 2.2; conductivity: 5850 µs/cm; F − : 460 mg/L; NH 4+ -N: 11.4 mg/L; SO 4 2− : 280 mg/L; total phosphorus (TP): 2.5 mg/L; SiO 2 : 10.3 mg/L; Al 3+ : 0.70 mg/L; Fe 2+ : 21.7 mg/L; and Mg 2+ : 0.1 mg/L.…”

Section: Materials and Reagentsmentioning

confidence: 99%

“…According to the existing literature, calcium fluoride (CaF 2 ) precipitation methods for the removal and recovery of fluoride ions as valuable resources can be one such useful process [17]. This technology is known to have the potential to replace conventional chemical coagulation/precipitation methods, producing minimal waste and generating high-purity fluoride calcium crystals [18][19][20]. Despite having such large potential, there are only a handful of studies on calcium fluoride crystallization mechanisms to treat fluoride-containing wastewater, and there are fewer studies on the effect of various process parameters.…”

Section: Introductionmentioning

confidence: 99%

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Optimization of Calcium Fluoride Crystallization Process for Treatment of High-Concentration Fluoride-Containing Semiconductor Industry Wastewater

Sinharoy,

Lee,

Chung

2024

IJMS

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This study utilized a fluidized bed reactor (FBR) for fluoride removal from high-concentration fluoride-ion-containing simulated semiconductor industry wastewater and recovered high-purity CaF2 crystals. The effects of hydraulic retention time (HRT), pH, Ca2+ to F− ratio, upflow velocity, seed size and seed bed height were investigated by performing lab-scale batch experiments. Considering fluoride removal and CaF2 crystallization efficiency, 5 h HRT, pH 6, seed height of 50 cm and [Ca2+]/[F−] ratio of 0.55 (mol/mol) were found to be optimum. The effect of the interaction between the important process parameters on fluoride removal was further analyzed using response surface methodology (RSM) experimental design. The results showed that all the individual parameters have a significant impact (p = 0.0001) on fluoride removal. SEM-EDX and FTIR analysis showed the composition of the crystals formed inside FBR. HR-XRD analysis confirmed that the crystalline structure of samples was mainly CaF2. The results clearly demonstrated the feasibility of silica seed material containing FBR for efficient removal and recovery of fluoride as high-purity calcium fluoride crystals.

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Section: Materials and Reagentsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Optimization of Calcium Fluoride Crystallization Process for Treatment of High-Concentration Fluoride-Containing Semiconductor Industry Wastewater

Sinharoy,

Lee,

Chung

2024

IJMS

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“…However, this drawback can be overcome by adjusting the flow rate as per the requirement based on actual reactor conditions. The synthetic wastewater used in this study was similar to semiconductor industry wastewater according to Sim et al [10] and had following characteristics: pH 2.2, conductivity 5,850 µs/cm, F ￚ 460 mg/L, NH 4+ -N 11.4 mg/L, SO4 2-280 mg/L, total phosphorus (TP) 2.5 mg/L, SiO2 10.3 mg/L, Al 3+ 0.70 mg/L, Fe 2+ 21.7 mg/L, and Mg 2+ 0.1 mg/L. The HRT and upflow velocity were maintained at 5 hours and 20 m/h, respectively.…”

Section: Upflow Velocity (M/h)mentioning

confidence: 99%

“…The semiconductor industry's own efforts to minimize its environmental impact include the development and implementation of cleaner technologies, recycling programs, and rigorous waste management practices [8,10]. Despite these efforts, proper disposal and handling of fluoridecontaining chemicals remains important to reduce potential negative effects on the environment and surrounding communities.…”

Section: Introductionmentioning

confidence: 99%

Process Intensification for Enhanced Fluoride Removal and Recovery As Calcium Fluoride Using Fluidized Bed Reactor

Sinharoy,

Lee,

Chung

2024

Preprint

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This study explored the feasibility of fluoride removal from simulated semiconductor industry wastewater and its recovery as calcium fluoride using fluidized bed crystallization. The continuous reactor showed best performance (>90% fluoride removal and >95% crystallization efficiency) at a calcium to fluoride ratio of 0.6 within first 40 days of continuous operation. The resulting particle size increased by more than double during this time along with a 36% increase in the seed bed height indicating deposition of CaF2 onto the silica seed. The SEM-EDX analysis showed the size and shape of the crystals formed along with high amount of Ca-F ions presence. The purity of the CaF2 crystals were determined to be 91.1% though ICP-OES analysis. Following the continuous experiment, different process improvement strategies are explored. The addition of excess amount of calcium resulted in an additional 6% fluoride removal, however, compared to this single stage process, a two-stage approach was found to be better strategy to achieve a low effluent fluoride concentration. The fluoride removal reached 94% with this two-stage approach under optimum condition of 4 + 1 h HRT combinations and a [Ca2+]/[F-] ratio of 0.55 and 0.7 for the two reactors, respectively. CFD simulation showed the impact of inlet diameter, bottom-angle shape and width and height ratio of the reactor on mixing inside reactor and possibility of further improvement in reactor performance by optimizing the FBR configuration.

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“…The semiconductor industry's own efforts to minimize its environmental impact include the development and implementation of cleaner technologies, recycling programs, and rigorous waste management practices [8,10]. Despite these efforts, proper disposal and handling of fluoride-containing chemicals remain important to reduce potential negative effects on the environment and surrounding communities.…”

Section: Introductionmentioning

confidence: 99%

Process Intensification for Enhanced Fluoride Removal and Recovery as Calcium Fluoride Using a Fluidized Bed Reactor

Sinharoy,

Lee,

Chung

2024

IJMS

View full text Add to dashboard Cite

This study explored the feasibility of fluoride removal from simulated semiconductor industry wastewater and its recovery as calcium fluoride using fluidized bed crystallization. The continuous reactor showed the best performance (>90% fluoride removal and >95% crystallization efficiency) at a calcium-to-fluoride ratio of 0.6 within the first 40 days of continuous operation. The resulting particle size increased by more than double during this time, along with a 36% increase in the seed bed height, indicating the deposition of CaF2 onto the silica seed. The SEM-EDX analysis showed the size and shape of the crystals formed, along with the presence of a high amount of Ca-F ions. The purity of the CaF2 crystals was determined to be 91.1% though ICP-OES analysis. Following the continuous experiment, different process improvement strategies were explored. The addition of an excess amount of calcium resulted in the removal of an additional 6% of the fluoride; however, compared to this single-stage process, a two-stage approach was found to be a better strategy to achieve a low effluent concentration of fluoride. The fluoride removal reached 94% with this two-stage approach under the optimum conditions of 4 + 1 h HRT combinations and a [Ca2+]/[F−] ratio of 0.55 and 0.7 for the two reactors, respectively. CFD simulation showed the impact of the inlet diameter, bottom-angle shape, and width-to-height ratio of the reactor on the mixing inside the reactor and the possibility of further improvement in the reactor performance by optimizing the FBR configuration.

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A review of semiconductor wastewater treatment processes: Current status, challenges, and future trends

Cited by 21 publications

References 78 publications

Optimization of Calcium Fluoride Crystallization Process for Treatment of High-Concentration Fluoride-Containing Semiconductor Industry Wastewater

Optimization of Calcium Fluoride Crystallization Process for Treatment of High-Concentration Fluoride-Containing Semiconductor Industry Wastewater

Process Intensification for Enhanced Fluoride Removal and Recovery As Calcium Fluoride Using Fluidized Bed Reactor

Process Intensification for Enhanced Fluoride Removal and Recovery as Calcium Fluoride Using a Fluidized Bed Reactor

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