Table 3. Experimental conditions and results.

Sample	R141b–effluent volume ratio	Heavy metal ions	C0(mg/L)	C11(mg/L)	C12(mg/L)	C2(mg/L)	Re without washing (%)	Re with washing (%)	Ef	Yw (%)
S1	1:4	Cr3+	140.4	–	0.2108	257.5	–	99.85	1.8340	–
		Cu2+	143.9	–	0.3568	261.6	–	99.75	1.8179
		Ni2+	136.5	–	0.2444	250.0	–	99.82	1.8315
		Zn2+	133.7	–	0.3197	250.6	–	99.76	1.8743
S2	1:6	Cr3+	96.70	28.99	9.936	126.4	70.02	89.72	1.3071	61.67
		Cu2+	104.4	29.37	9.583	133.9	71.87	90.82	1.2826
		Ni2+	97.12	27.40	9.781	123.5	71.79	89.93	1.2716
		Zn2+	93.36	30.04	11.19	122.6	67.82	88.01	1.3132
S3	1:5	Cr3+	96.70	38.11	15.87	159.4	60.59	83.58	1.6487	71.67
		Cu2+	104.4	38.62	14.69	162.8	63.00	85.93	1.5599
		Ni2+	97.12	37.06	15.26	155.6	61.83	84.28	1.6022
		Zn2+	93.36	39.75	16.54	153.5	57.41	82.28	1.6442
S4	1:4	Cr3+	96.70	45.45	23.12	178.9	53.00	76.09	1.8501	80.00
		Cu2+	104.4	45.54	22.56	190.5	56.38	78.39	1.8247
		Ni2+	97.12	43.45	20.60	175.3	55.26	78.79	1.8050
		Zn2+	93.36	46.63	22.39	174.5	50.05	73.13	1.8691