Anticorrosive efficacy and adsorptive study of guar gum with mild steel in acidic medium

Journal of Analytical Science and Technology

Table 4 Calculated values of apparent activation energy (Ea) and Heat of adsorption (Q) of guar gum on mild steel in 1N HCl, H₂SO₄ and HNO₃ medium

Guar gum concentration (ppm)	Medium	Ea (kJ mol⁻¹)				Qads (kJ mol⁻¹)
Guar gum concentration (ppm)	Medium	6 h	24 h	48 h	72 h	6 h	24 h	48 h	72 h
0	1N HCl	9.27250789	2.90507331	0.9139064	1.36911847	–	–	–	–
250		11.848584	5.58216111	12.9549107	5.19003643	−3.75007014	−4.43960607	−5.22802254	−4.21395543
500		12.8788011	6.29318179	4.32023085	7.31956056	−7.53960158	−7.82935384	−9.85802469	−10.7977925
750		21.6914682	10.3215288	4.47333994	2.8048226	−10.0039872	−10.915953	−12.1317652	−14.818384
1000		6.56409778	10.947072	10.1705685	9.94213687	−7.6629907	−10.8511463	−13.051503	−17.5339037
0	1N H₂SO₄	8.8401921	3.52688474	1.41960241	1.50081477	–	–	–	–
250		16.5049372	13.2543419	20.1025875	12.0519032	−6.17484905	−6.84773222	−10.0018618	−11.1406732
500		17.1777765	19.3215751	12.9564535	10.8190683	−6.80674183	−8.4132127	−10.1549509	−12.5647234
750		22.8243155	12.1771338	20.733607	15.6261701	−5.22040277	−5.85683963	−7.75697335	−9.24900021
1000		17.421718	21.6080439	22.5823843	32.02365	−3.34592498	−3.79544558	−5.29988713	−7.99889198
0	1N HNO₃	1.77304033	3.55516654	0.79157225	1.08495861	–	–	–	–
250		8.30698807	10.1277979	3.89375612	5.43939158	−3.36869057	−2.96013092	−2.41242305	−2.20720793
500		5.32116501	7.53342455	3.0589423	3.12703952	−4.84997347	−2.89713752	−2.05965033	−1.9731825
750		8.84421126	5.7499852	2.72675645	3.5886785	−1.79641201	−1.70305171	−1.74738879	−1.82442233
1000		7.05913228	7.25875797	4.03907321	3.7658194	−1.76463022	−1.85561621	−1.92276054	−2.03325308