Table 4 Summary of the measured pH values before and after the sorption process of removal phosphate ions and the sorption capacity for seaweed and seaweed-derived samples (C₀ 100 mg/L, C_s 1 g/L, 4 h)

1.98

1.98

2.02

2.60

2.01

2.32

0.873 ± 0.448

2.02

2.82

0.566 ± 0.378

2.04

2.59

10.7 ± 3.68

3.04

3.04

3.00

5.10

2.99

6.07

2.64 ± 1.32

3.01

7.42

7.36 ± 1.32

3.02

6.98

7.63 ± 2.30

4.05

4.05

4.00

5.41

4.03

6.30

2.22 ± 0.94

4.03

8.44

7.31 ± 1.56

4.02

7.07

7.34 ± 2.80

5.01

5.01

5.04

5.69

5.04

6.55

1.06 ± 0.02

5.00

9.16

9.01 ± 1.79

5.03

6.92

8.49 ± 3.29

6.01

6.01

6.01

6.09

5.96

6.65

1.04 ± 0.19

6.02

8.87

6.80 ± 0.66

6.04

6.98

12.9 ± 7.60

7.05

7.05

6.98

6.70

6.99

7.16

2.90 ± 0.87

6.98

9.58

6.16 ± 1.58

6.98

7.30

8.91 ± 6.34

7.96

7.96

7.99

7.06

7.98

8.20

2.60 ± 0.28

8.02

9.89

8.92 ± 0.14

8.03

8.44

12.8 ± 10.2