Core Process System of Reverse Osmosis Membrane in the Electroplating Industry

1. Quality Classification Treatment Process

• Cyanide-containing wastewater: Pre-treated by alkaline chlorination to break cyanide, then enters the RO system (pH 6-8, pressure 2.5MPa), with a cyanide removal rate of >99.9%.
• Chromium-containing wastewater: Through two-stage reduction (sodium pyrosulfite + ferrous sulfate) to convert Cr⁶⁺ to Cr³⁺, combined with tubular microfiltration (TMF) pretreatment, the chromium concentration in RO concentrate can reach 12g/L.
• Nickel/copper-containing wastewater: Pretreated with selective chelating resin, combined with anti-pollution RO membrane (flux 28LMH), the purity of nickel recovery reaches 99.5%.
• Organic wastewater: Pretreated by ozone catalytic oxidation (catalyst loading 3g/L) + nanofiltration (NF270), the COD interception rate is 85%.

2. Integrated Membrane Process System

• Primary: Spiral RO (recovery rate 60-70%)
• Secondary: Disc tube RO (DTRO, recovery rate 85-90%)
• Tertiary: High pressure RO (HPRO, pressure 10MPa) treats concentrate, total recovery rate >97% Membrane electrolysis coupling system:
• RO concentrate enters the electrolytic槽 (current density 300A/m²), metal deposition efficiency increases to 95%
• Case of an enterprise in Jiangsu: Nickel recovery increased from 8.2 tons/year to 15.6 tons, electricity consumption decreased by 42%

3. Key Process Parameter Optimization

4. Special Membrane Application Process

• Acid-resistant RO membrane (pH 1-4):
  • Used for chromium plating rinse water treatment, with 99.99% chromium acid interception rate
  • Shenzhen factory application case: Chromium acid reuse cost reduced to 1/3 of new solution
• Thermal RO system:
  • Preheat wastewater to 45℃ (using waste heat), increase membrane flux by 30%
  • Zhejiang project data shows: Energy consumption decreased by 22%, desalination rate maintained at 99.2%
• Forward Osmosis (FO)-RO Combined Use:
  • Use high osmotic pressure of electroplating solution to drive water recovery, reduce energy consumption by 40%
  • Experimental data shows: Nickel ion reverse diffusion <0.1mg/L

5. Intelligent Process Control

• Digital twin system:
  • Real-time simulation of membrane system operation status, predict pollution development (error <5%)
  • Shanghai demonstration project: Membrane replacement cycle prediction accuracy 92%
• AI parameter optimization:
  • Dynamically adjust operating pressure and recovery rate based on LSTM neural network
  • Suzhou enterprise application case: System energy efficiency increased by 18%, manual intervention reduced by 70%
• IoT monitoring platform:
  • Deploy 500+ sensors (pressure, conductivity, ORP, etc.)
  • Abnormal operating conditions response time shortened to 15 seconds

6. Resource Recycling Closed-loop Process

• Water circulation system:
  • Rinse water→Sand filter→Ultrafiltration→RO→EDI→Electroplating tank
  • Water quality meets ASTM D5091 standard, conductivity <5μS/cm
• Metal recovery chain:
  • RO concentrate→Electrolytic deposition→Vacuum melting→Electroplating raw material
  • Foshan enterprise achieved copper powder (purity 99.98%) direct supply to production line
• Waste salt resource utilization:
  • Use differential crystallizer (temperature difference control ±0.5℃)
  • Separate nickel sulfate, sodium chloride, boric acid, etc. into industrial raw materials

7. Zero Liquid Discharge (ZLD) Process Package

8. Engineering Practice Cases

• Guangdong Hardware Electroplating Park:
  • Treatment scale: 2000m³/d
  • Process: TMF+RO+EDR
  • Effect: Nickel recovery rate 95.3%, water reuse cost 1.2 yuan/ton
• Chongqing Automotive Electroplating Project:
  • Uses vibrating membrane (VSEP) pretreatment technology
  • Membrane pollution rate reduced by 65%, cleaning agent usage reduced by 40%
• Japanese-funded Electronic Electroplating Plant:
  • Implements RO-ion exchange combined process
  • Heavy metal content in effluent <0.05mg/L, meets Japanese JIS K5600 standard

9. Process Economic Analysis

• Membrane system: 42% (including spare parts)
• Pretreatment unit: 28%
• Automated control: 15%
• Auxiliary facilities: 15%

• Power consumption: 1.8-2.5
• Membrane replacement: 0.6-1.2
• Chemicals: 0.3-0.8
• Labor: 0.2-0.5 Total cost: 2.9-5.0 (35-50% lower than traditional process)

• Metal recycling revenue: 1.2-2 years
• Water cost saving revenue: 3-5 years

10. Process Innovation Directions

• Membrane material innovation:
  • Develop MXene/polyamide composite membrane to enhance anti-pollution performance (experimental flux increased by 50%)
  • Self-healing membrane coating technology to achieve automatic repair of nanoscale damage
• Process coupling innovation:
  • Membrane distillation (MD)-RO combined use for high-temperature wastewater treatment
  • Electro adsorption-RO combined process for low-concentration wastewater treatment
• Energy recovery system:
  • Pressure exchanger (PX) recovers concentrate residual pressure, saves energy by 30-40%
  • Osmotic power generation module, conversion efficiency reaches 15%