Treatment of Strongly Acidic Indium‑Bearing Wastewater via Indium‑Removal Resin: Adsorption‑Regeneration Validation

August 11, 2026

1. Raw Water Conditions

Indium concentration: 296.264 mg/L
pH: Strongly acidic
Appearance: Colorless, transparent solution with slight turbidity

2. Dynamic Adsorption Experimental Data (Indium Content in Multi-Cycle Effluent)

Cycle	Sampling Point (BV)	Effluent Indium Content (mg/L)	Remarks
Cycle 1	10 BV	0.172	Initial adsorption stage
	20 BV	0.143	Stable operation stage
	20–40 BV	0.318	Value still far below 1 mg/L
Cycle 2	1–38 BV	0.074	Stable compliance stage
	38–52 BV	0.325	Slight concentration rise
	53 BV	0.188	Concentration falls back
Cycle 3	1–50 BV	0.065	Stable compliance stage
	51–54 BV	0.055	Minimum value in the cycle
	55–59 BV	0.074	Maintains low concentration level
Cycle 4	1–52 BV	0.122	Stable performance in early stage
	53–62 BV	0.986	Approaching 1 mg/L breakthrough threshold
	63–69 BV	1.484	Breakthrough & concentration rising stage

Key Data Highlights

Across four cycles, indium concentration in most effluent samples stays steadily below 1 mg/L, with a minimum recorded value of 0.055 mg/L;
The indium concentration of feed liquid is 296.264 mg/L, and the overall removal rate consistently exceeds 99.5%;
Breakthrough occurs at 63–69 BV in the 4th cycle (1.484 mg/L), which can be referenced as the trigger point for resin regeneration.

3. Regeneration & Elution Data

Regenerant: 15%–20% hydrochloric acid
Indium concentration in eluate: 8674 mg/L
Compared with the raw feed liquid (296 mg/L), the enrichment concentration ratio reaches approximately 29 times, which facilitates subsequent indium recovery processes.

4. Stability Verification

After four complete adsorption-regeneration cycles, the effluent indium concentration at the initial stage of each cycle (e.g., 0.065 mg/L for 1–50 BV in Cycle 3) shows no adsorption performance decline versus the initial stage of Cycle 1 (0.172 mg/L at 10 BV).

The resin exhibits excellent reusability stability and great potential for industrial cyclic application.

5. Conclusion

This specialty resin delivers highly efficient adsorption performance for strongly acidic wastewater with high indium concentration (around 300 mg/L). It can stably lower effluent indium content below 1 mg/L, delivers outstanding enrichment performance after regeneration (eluate indium concentration up to 8674 mg/L), and retains stable adsorption capacity over multiple cycles. It is well suited for advanced treatment and resource recovery of indium-containing wastewater.