Potential use of Ulva intestinalis-derived biochar adsorbing phosphate ions in the cultivation of winter wheat Tristicum aestivum

Bioresources and Bioprocessing

Table 7 Assigned peaks visible in the FTIR spectra for seaweed and seaweed-derived bioproducts

Raw material/biochar	FTIR range	Peak	Chemical compound groups
Seaweed	3100–3600	3531	Hydroxyl groups
		3382
		3339
		3287
		3274
	2900–2950	2931	Aliphatic groups
	1300–1700	1632	Carboxyl groups
		1540
		1408
		1320
		1225
	990–1150	1028	Phosphate groups
	620–900	831	Aromatic groups
	620–900	779	Aromatic groups
	< 600	463	Alkyl halides groups
		448
		415
Modified seaweed	3100–3600	3501	Hydroxyl groups
	3100–3600	3332	Hydroxyl groups
	1300–1700	1608	Carboxyl groups
	990–1150	1025	Phosphate groups
Biochar obtained at 700 °C	1300–1700	1465	Carboxyl groups
	990–1150	990	Phosphate groups
	620–900	776	Aromatic groups
	620–900	693	Aromatic groups
	< 600	437	Alkyl halides groups
	< 600	425	Alkyl halides groups
Biochar obtained at 700 °C enriched with phosphate ions	1300–1700	1384	Carboxyl groups
	990–1150	1007	Phosphate groups
	620–900	872	Aromatic groups
	< 600	411	Alkyl halides groups
Modified biochar obtained at 700 °C	3100–3600	3656	Hydroxyl groups
		3638
		3370
	1300–1700	1634	Carboxyl groups
		1560
		1521
		1475
		1439
	990–1150	1149	Phosphate groups
	620–900	895	Aromatic groups
	620–900	845	Aromatic groups
Modified biochar obtained at 700 °C enriched with phosphate ions	3100–3600	3069	Hydroxyl groups
	2900–2950	2931	Aliphatic groups
	1300–1700	1429	Carboxyl groups
	990–1150	996	Phosphate groups
	620–900	856	Aromatic groups
	620–900	775	Aromatic groups
	< 600	411	Alkyl halides groups