Kinetics and the mass transfer mechanism of hydrogen sulfide removal by biochar derived from rice hull

Figures & data

Figure 1. The schematic diagram of the experimental setup for hydrogen sulfide removal.

Table 1. Physicochemical characteristics of the three different biochars and activated carbon.

Property	SR100	SR200	SR300	SR400	SR500
pH	7.25 ± 0.02	7.51 ± 0.01	7.86 ± 0.02	8.74 ± 0.03	10.54 ± 0.02
N (%)	1.66 ± 0.03	1.08 ± 0.04	0.93 ± 0.03	0.56 ± 0.04	0.41 ± 0.02
C (%)	72.94 ± 0.06	66.32 ± 0.07	53.59 ± 0.05	41.45 ± 0.05	33.27 ± 0.04
O (%)	19.2 ± 0.03	17.4 ± 0.05	16.7 ± 0.06	14.5 ± 0.03	12.2 ± 0.02
H (%)	3.5 ± 0.04	2.3 ± 0.02	1.7 ± 0.03	1.1 ± 0.01	0.9 ± 0.02
SA (m^2/g)	4.35 ± 0.04	24.01 ± 0.08	69.34 ± 0.18	98.27 ± 0.15	115.49 ± 0.18

Notes: SA = Brunauer-Emmett-Teller (BET) N₂-specific surface area.

Figure 2. Breakthrough curves of H₂S on rice hull–derived biochars pyrolyzed at different temperatures.

Table 2. H₂S breakthrough time, saturation time, and H₂S breakthrough capacity for the different biochars.

Sample	Breakthrough Time (min)	Saturation Time (min)	Breakthrough Capacity (mg/g)
SR100	5	20	2.09 ± 0.05
SR200	10	45	2.65 ± 0.08
SR300	35	150	16.3 ± 0.11
SR400	50	185	20.8 ± 0.13
SR500	620	1645	382.7 ± 0.16

Figure 3. Schematics of gas flow through the biochar bed.

Figure 4. Relationship of ln(C/(C₀ − C) and t.

Figure 5. Comparison of calculated breakthrough curves with experimental results.