NF selectivity, salt fractionation and target-ion rejection deviation
Use this when nf selectivity, salt fractionation and target-ion rejection deviation is observed but the cause remains unclear. The diagnostic checks measurement and sampling, operating changes, issue location, and key evidence before suggesting likely causes and the next useful check.
First time here? Start with this
You do not need every data point before you begin
The system asks one discriminating question at a time and updates the candidate causes on the right. Answer from current facts; choose unknown or defer a question when the evidence is not available.
- 1
Confirm the issue
Check whether the symptom is reproducible and whether the measurement or observation is reliable.
- 2
Narrow the causes
Continue through operating changes, issue location, and available inspection results.
- 3
Read the live result
Candidate causes, support, counter-evidence, conflicts, and next actions update as you answer.
This tool analyzes information you already have. It does not insert a safety screen or use safety status to stop the diagnosis. If an alarm, leak, or injury is happening now, follow the site emergency procedure directly.
Automatic troubleshooting · Selections are not uploaded
Only one question is shown at a time. Answer from current facts or defer an unknown item. Possible causes and next checks update on the right as you answer.
- 1Data validity
- 2Operating changes
- 3Issue location
- 4Further confirmation
Question progress
0/30
- Answered
- 0
- To confirm
- 30
- Clues found
- 0
Load a test scenario
Next question
Phase 1 · Data validity
Is the control objective and formula permeate concentration, ion rejection, selectivity factor, or stream purity?
The system asks the question most useful for separating possible causes. Unknown or deferred items are not treated as the opposite conclusion.
I have more test or inspection resultsOptionalAdd laboratory analysis, normalized calculations, or checks completed by trained personnel when available. These fields are optional.
View rule sources (14)Standards, regulations, OEM material, and peer-reviewed literature used to audit the diagnostic logic. You do not need to read them before starting.
Each rule cites material directly relevant to its judgment. Current OEM and site procedures remain controlling.
- A-current-oem-technical-manual · DuPont Water Solutions · 2026FilmTec Reverse Osmosis/Nanofiltration Membranes Technical Manual, Rev. 19
- A-current-oem-product-datasheet · DuPont Water Solutions · 2025FilmTec NF270-440 Element Product Data Sheet, Rev. 2
- A-current-oem-product-datasheet · Hydranautics · 2025ESNA1-LF-LD Product Data Sheet
- A-current-industry-standard · ASTM International · 2023ASTM D4194-23 Standard Test Methods for Operating Characteristics of Reverse Osmosis and Nanofiltration Devices
- A-industry-standard · ASTM International · 2019ASTM D6161-19 Standard Terminology Used for Microfiltration, Ultrafiltration, Nanofiltration, and Reverse Osmosis Membrane Processes
- A-current-international-standard · International Organization for Standardization · 2026ISO 25175:2026 Marine technology — Standard test methods for performance of RO and NF membrane elements
- A-current-international-standard · International Organization for Standardization · 2020ISO 23044:2020 Guidelines for softening and desalination of industrial wastewater for reuse
- A-industry-consensus-standard · American Water Works Association · 2022AWWA B114-22 Reverse Osmosis and Nanofiltration Systems for Water Treatment
- A-government-analytical-method · U.S. Environmental Protection Agency · 1997EPA Method 300.1 Determination of Inorganic Anions in Drinking Water by Ion Chromatography
- A-government-analytical-method · U.S. Environmental Protection Agency · 1994EPA Method 200.7 Determination of Metals and Trace Elements in Water and Wastes by ICP-AES
- A-peer-reviewed-primary-study · Journal of Membrane Science · 2005The role of membrane charge on nanofiltration performance
- A-peer-reviewed-primary-study · Desalination · 2024Negative rejection phenomenon in the mixed salt nanofiltration: Law and mechanism
- A-current-federal-regulation · Occupational Safety and Health Administration · 198929 CFR 1910.147 The control of hazardous energy
- A-current-federal-regulation · Occupational Safety and Health Administration · 201229 CFR 1910.1200 Hazard Communication