Removal of Fe2+ and Mn2+ from Polluted Groundwater by Insoluble Humic Acid/Tourmaline Composite Particles

Abstract

Insoluble humic acid/tourmaline composite particles (IHA/TM) were prepared by combining inorganic tourmaline (TM) with the natural organic polymer humic acid (HA) and carbonizing them at 330 °C to study the removal characteristics and mechanism of Fe2+ and Mn2+. The results showed that the optimal ratio of TM to IHA is 2:3. When the temperature of the IHA/TM composite particles was 35 °C and the pH was 6, the adsorption of Fe2+ and Mn2+ by IHA/TM reached equilibrium at 240 min. The optimum dose of the adsorbent was 10 g/L, and the equilibrium adsorption capacities of Fe2+ and Mn2+ were 5.645 mg/g and 3.574 mg/g, respectively. The process of IHA/TM adsorption of Fe2+ and Mn2+ in water was spontaneous, endothermic and sustainable, and cooling was not conducive to adsorption. The pseudo-second order kinetic equation can well reflect the adsorption mechanism of IHA/TM on Fe2+ and Mn2+, and the Langmuir adsorption model better describes the isothermal adsorption behaviour. The material characterisation and adsorption experiments indicate that surface coordination and chemical precipitation are the main mechanisms of Fe2+ and Mn2+ removal by IHA/TM.

Mesoporous Activated Carbon from Bamboo Waste via Microwave-Assisted K2CO3 Activation: Adsorption Optimization and Mechanism for Methylene Blue Dye

“…Here, it was observed that with greater values of BWAC dose from 0.02 g to 0.08 g, the MB removal drastically increased from 55% to 70%, respectively. A higher amount of dose provides more binding sites for MB dye molecules and increases the removal capacity [43]. On the other hand, the same observation was seen for pH, and it was seen that with an alteration in pH from 4 to 10, MB dye removal improved from 40% to 60%, respectively.…”

“…The ANOVA data for MB removal from aqueous solutions by BWAC are presented in Table 4. The ANOVA data are generally based on probability (p) and F-value, and p-values of lower than 0.05 indicate that the model is a statistically efficient, accurate, and significant one, where the findings are not random [41][42][43][44]. Here, the p-value of the model was less than 0.0001 with an F-value of 31.49, which confirms that the model was significant.…”

Dynamic Adsorption Properties of Insoluble Humic Acid/Tourmaline Composite Particles for Iron and Manganese in Mine Wastewater

“…Preparation of IHA/TM composite particles: IHA/TM composite particles were prepared according to the reference of our research group [25]. First, insoluble humic acid (IHA) was prepared, and then the optimal preparation conditions for IHA/TM composite particles were determined by investigating different mixing ratios of TM:IHA (1:3, 2:3, 1:1, 3:2 and 3:1), mixing times (6 h, 12 h, 18 h, 24 h and 30 h), calcination temperatures (240 • C, 270 • C, 300 • C, 330 • C and 360 • C) and calcination times (30 min, 60 min, 90 min, 120 min, 150 min and 180 min) on the removal effect of Fe 2+ and Mn 2+ .…”