ENHANCED CHEMICAL CLEANING OF SRS WASTE TANKS TO IMPROVE ACTINIDE SOLUBILITY

AbstractOxide/Nitride dielectric stack is widely used as the standard dielectric for DRAM capacitors. The influence of the chemical cleaning prior to the stack formation has been studied in this work. As a result, morphological data such as stack surface roughness (Atomic Force Microscopy) and silicon nitride (SiN) incubation time for growth are comparable for all the studied cases on <Si>. However, Tof-SIMS exhibits different oxygen content at the Si/stack interface following the different chemical treatments. Electrical measurements show comparable C-V and I-V results, for the same Equivalent Oxide Thickness (same capacitance at strong accumulation i.e.-3V) while the different studied interfaces bring different interface states density with lower values for higher interfacial oxygen content. For DRAM applications, a clear improvement in electrical characteristics is obtained under low interfacial oxygen content conditions. Results are compared in embedded-DRAM cells for which we developed an industrially compatible dielectric deposition sequence to obtain minimum leakage current with maximum specific capacitance and no particular linking constraints.

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Leakage Current Reduction of Ni-MILC Poly-Si TFT Using Chemical Cleaning Method

Korean Journal of Materials Research ◽

10.3740/mrsk.2018.28.8.440 ◽

2018 ◽

Vol 28 (8) ◽

pp. 440-444

Author(s):

Kwang-Jin Lee ◽

◽

Doyeon Kim ◽

Duck-Kyun Choi ◽

Woo-Byoung Kim

Keyword(s):

Leakage Current ◽

Chemical Cleaning ◽

Cleaning Method ◽

Current Reduction

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Enhancing Efficiency of Full-Scale Ultrafiltration Membrane Treatment for Increased Capacity and Lower Operating Costs

Water Practice & Technology ◽

10.2166/wpt.2010.086 ◽

2010 ◽

Vol 5 (4) ◽

Author(s):

M.C. White PE ◽

M.J. Kosterman

Keyword(s):

Citric Acid ◽

Water Treatment ◽

Operating Costs ◽

Percent Reduction ◽

Chemical Cleaning ◽

Optimization Program ◽

Systematic Optimization ◽

Percent Increase ◽

Treatment Facilities ◽

Membrane Treatment

At time of commissioning, the Racine, Wisconsin, USA ultrafiltration (UF) membrane treatment system fail short of meeting its operational goals concerning capacity and chemical cleaning intervals. The systematic optimization of this 189-million-litre-per-day (MLD) capacity UF system provided tangible operational benefits, which included a 30-percent reduction in power use, a 50-percent reduction in chlorine chemical use, a 36-percent reduction in citric acid use and a simultaneous 7-percent increase in net treatment capacity of the system. In addition, the optimization program reduced the level of buildup of foulants on the surface of the membranes. This paper summarizes the optimization procedures followed at Racine, discussing how similar measures may be applicable to other water treatment facilities.

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Low-pressure membrane filtration with unconventional coagulation regimes

Water Science & Technology Water Supply ◽

10.2166/ws.2005.0032 ◽

2005 ◽

Vol 5 (5) ◽

pp. 1-8 ◽

Cited By ~ 1

Author(s):

K.Y. Choi ◽

B.A. Dempsey

Keyword(s):

Activated Carbon ◽

Membrane Filtration ◽

Membrane Surface ◽

Cross Flow ◽

Chemical Cleaning ◽

Sand Filters ◽

Charge Neutralization ◽

Floc Size ◽

Filtration System ◽

Pre Treatment

The objective of the research was to evaluate in-line coagulation to improve performance during ultrafiltration (UF). In-line coagulation means use of coagulants without removal of coagulated solids prior to UF. Performance was evaluated by removal of contaminants (water quality) and by resistance to filtration and recovery of flux after hydraulic or chemical cleaning (water production). We hypothesized that coagulation conditions inappropriate for conventional treatment, in particular under-dosing conditions that produce particles that neither settle nor are removed in rapid sand filters, would be effective for in-line coagulation prior to UF. A variety of pre-treatment processes for UF have been investigated including coagulation, powdered activated carbon (PAC) or granular activated carbon (GAC), adsorption on iron oxides or other pre-formed settleable solid phases, or ozonation. Coagulation pre-treatment is often used for removal of fouling substances prior to NF or RO. It has been reported that effective conventional coagulation conditions produced larger particles and this reduced fouling during membrane filtration by reducing adsorption in membrane pores, increasing cake porosity, and increasing transport of foulants away from the membrane surface. However, aggregates produced under sweep floc conditions were more compressible than for charge neutralization conditions, resulting in compaction when the membrane filtration system was pressurized. It was known that the coagulated suspension under either charge-neutralization or sweep floc condition showed similar steady-state flux under the cross-flow microfiltration mode. Another report on the concept of critical floc size suggested that flocs need to reach a certain critical size before MF, otherwise membranes can be irreversibly clogged by the coagulant solids. The authors were motivated to study the effect of various coagulation conditions on the performance of a membrane filtration system.

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