Recovery of iron hydroxides from electro-coagulated sludge for adsorption removals of dye wastewater: Adsorption capacity and adsorbent characteristics
Recovery of iron hydroxides from electro-coagulated sludge for adsorption removals of dye wastewater: Adsorption capacity and adsorbent characteristics
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DOI：
10.1016/j.surfin.2020.100439
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发表时间：
2020-03-01
影响因子：
6.2
通讯作者：
Aragaw, Tadele Assefa
中科院分区：
文献类型：
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作者：
Aragaw, Tadele Assefa
本研究的目的是考察生铁和焙烧的氢氧化铁/氧化物污泥吸附去除DR28染料的潜力。以工业废水处理厂的电絮凝污泥为原料，制备了一种用于直接红28染料(DR28)脱色的诺贝尔吸附剂。采用浸渍法制备了EC污泥吸附剂，并在一定的温度范围内进行了焙烧。采用Zeta电位仪、X射线衍射仪和傅立叶变换红外光谱仪对生料和焙烧后的EC污泥吸附剂的表面性质进行了考察。考察了生料和焙烧EC污泥吸附剂的基本操作参数(溶液pH值、温度、染料初始浓度)。衍射谱表明，晶态赤铁矿是在焙烧过程中产生的，其强度随着温度的升高而增强。吸附平衡用Langmuir方程和Freundlich方程模拟，吸附动力学用准一级和二级方程模拟。结果表明，DR28染料的吸附为化学吸附，吸附表面与染料之间存在较强的相互作用。在常温下，混合时间为20min，吸附剂用量为0.5g，染料初始浓度为20 mg/L，溶液pH=2，焙烧前后的EC污泥吸附剂对DR28染料的吸附容量分别为1.262 mg/g和1.252 mg/g。吸附动力学模型数据符合准秒级。在pH值为2、常温为20 mg/L、1g/100ml的条件下反应1h，废水的去除效率可达97%。直接红28染料的高吸附能力和纺织废水处理厂污泥利用的成本效益使其在染料去除方面具有潜在的吸引力。
The aims of this research work was to investigate the potentials of raw and calcined iron hydroxides/oxides sludge adsorption for DR28 dye removal. The adsorbent is prepared from electro-coagulated (EC) sludge in industrial wastewater treatment plant, as a Nobel adsorbent for decolorizing direct red 28 dye (DR28). The EC sludge adsorbent were prepared with soaking processes and calcination in a range of temperature. The surface properties of raw and calcined EC sludge adsorbent were examined using Zeta Potential, XRD and FTIR. Basic (effect of solution pH, temperature, initial dye concentration) operation parameters were examined for raw and calcined EC sludge adsorbent. The diffraction patter suggests that the crystalline hematite are produced during calcination and increases its intensity as temperature increases. Langmuir and Freundlich Equation were used to model the adsorption equilibrium; and pseudo first and second order Equation were used to model the adsorption kinetics. The results suggested that the adsorption of DR28 dye is chemisorption, the interaction between the adsorbent surfaces with dye is strong. The Langmuir adsorption capacity of DR28 dye with raw and calcined EC sludge adsorbent was calculated as 1.262 mg/g and 1.252 mg/g respectively with experimental conditions: mixing time=20 min, adsorbent dosage=0.5 grams, initial dye concentration=20 mg/L and solution pH=2 at ambient temperature. The adsorption kinetics model data were consistent with the pseudosecond-order. The removal efficiency of 97% was recorded at pH 2, ambient temperature 20 mg/l concentration and 1 g/100 ml for 1 hour. High direct red 28 dye uptake capability and cost-effectiveness of sludge utilization from textile wastewater treatment plant make it potentially attractive for dye removal.