Sulfur Nanoparticles Synthesis and Characterization from H2S Gas, Using Novel Biodegradable Iron Chelates in W/O Microemulsion

Table 1 Screening of iron chelate systems

Iron salt	Chelating agent	Molar ratio	Reaction time (min)	Sulfur recovered mg/gm of iron chelate	% purity Sulfur^a
FeCl₃	Citric acid	1:2	36	184.20	>99
	Malic acid	1:3	15	499	>99
	Gluconic acid	1:3	5	27.7	83.71
Fe₂(SO₄)₃	Citric acid	1:2	25	137.8	97.5
	Malic acid	1:3	37	235	>99
	Gluconic acid	1:3	39	51	88.44
Fe₂(NO₃)₃	Citric acid	1:2	10	116,83	75.96
	Malic acid	1:3	5	290.88	94
	Gluconic acid	1:3	20	90	99

^aThe precipitate besides sulfur also contains C, N, H, and Fe, etc., as shown by elemental analysis