摘要
提出了一种改进的电凝聚法回收高盐废弃卤水中硫酸盐的方法。该方法基于使用高/中等碱性固体，即氧化钙(CaO)、氢氧化钡(Ba(OH)_2)、羟乙基纤维素(HEC)和钢包炉渣(LFS)回收硫酸盐，这些固体以特定浓度加入高盐度水中，并结合以特定电流密度进行电凝聚。该方法不需要预先的化学沉淀，将所需的能量输入最小化，并且可以使用从固体混合物中分离硫酸盐的常规方法进一步纯化收集的固体产物。该系统包括在特定操作和混合条件下具有碱性固体的电凝聚单元。电凝聚反应器采用矩形铝板作为电极。使用电源施加4.5-22.5 mA/cm~2的电流密度。该方法涉及在中等至高pH条件和特定阳极电位下在阳极产生电子。阴极有利于氢气和羟基离子的产生，有效地改善了溶解硫酸盐组分的解离。在CaO存在下,化学沉淀与电凝聚相结合,处理4h后,实际废盐水中硫酸盐的去除率从6051mg/l提高到196 mg/l。此外，HEC的硫酸盐去除率达到88%，LFS的硫酸盐去除率达到87%，氢氧化钡的硫酸盐去除率达到98%。此外，处理后的卤水中钡离子减少了64%。该方法特别导致固体化合物沉淀，硫酸钙(CaSO4)使用CaO和LFS，硫酸钡(BaSO_4)使用Ba(OH)_2，酸性品红(C_(20)H_(12)N_3Na_2O_9S_3)使用HEC。与传统的混合工艺相比,改进后的方法使能量从14.1 kW h/kg SO_4~(2-降至8.5kW h/kg SO_4~(2-)?compared,降低了40%。
Abstract
A modified electrocoagulation method is proposed for the recovery of sulfate from high salinity reject brine. This method is based on recovering sulfate using highly/moderately alkaline solids, namely, calcium oxide (CaO), barium hydroxide (Ba(OH)_2), hydroxyethyl cellulose (HEC), and ladle furnace slag (LFS), which are added to high salinity water at specific concentrations, in combination with electrocoagulation at specific current densities. This method does not require a prior chemical precipitation, minimizes the required energy input, and the collected solid products can be further purified using conventional methods of separating sulfate from solid mixtures. The system comprises an electrocoagulation unit with alkaline solids at certain operating and mixing conditions. Rectangular aluminium plates were used as electrodes for the electrocoagulation reactor. A current density of 4.5–22.5 mA/cm~2 is applied using a power source. The method involved generating electrons at the anode under moderate to high pH conditions and specific anodic potential. The cathode facilitated the production of hydrogen gas and hydroxyl ions, which effectively improved the dissociation of dissolved sulfate components. Combining the chemical precipitation and electrocoagulation in the presence of CaO in one process, a high sulfate removal was achieved from an initial concentration of 6051 mg/L to 196 mg/L in real reject brine after 4 h of treatment. Furthermore, the sulfate removal efficiency reached up to 88% using HEC, 87% using LFS, and 98% using barium hydroxide. In addition, the barium ions in the treated brine reduced up to 64%. The process led to the precipitation of solid compounds specifically, calcium sulfate (CaSO4) using CaO and LFS, and barium sulfate (BaSO_4) using Ba(OH)_2 and acid fuchsin (C_(20)H_(12)N_3Na_2O_9S_3) using HEC. The modified method resulted in an energy reduction of 40% from 14.1 kW h/kg SO_4~(2-) to 8.5 kW h/kg SO_4~(2-)?compared with the conventional hybrid process.
NETL
NSTL
Elsevier