Zidane Fatiha, Drogui Patrick, Lekhlif Brahim, Bensaid Jalila, Blais Jean-François, Belcadi Said, El Kacemi Kacem
Département de Chimie, Faculté des Sciences Ain Chock, Université Hassan II, Km 8, BP 5366, Maarif, Casablanca, Morocco.
J Hazard Mater. 2008 Jun 30;155(1-2):153-63. doi: 10.1016/j.jhazmat.2007.11.041. Epub 2007 Nov 21.
The colour and colour causing-compounds has always been undesirable in water for any use, be it industrial or domestic wastewaters. The discharge of such effluents causes excessive oxygen demand in the receiving water and then a treatment is required before discharge into ecosystems. This study examined the possibility to remove colour causing-compounds from effluent by chemical coagulation, in comparison with direct electrocoagulation. The inorganic coagulants (C1, C2 and C3) in the form of dry powder tested, were respectively produced from electrolysis of S1=[NaOH (7.5 x 10(-3)M)], S2=[NaCl (10(-2)M)], and S3=[NaOH (7.5 x 10(-3)M)+NaCl (10(-2)M)] solutions, using sacrificial aluminium electrodes operated at an electrical potential of 12 V. Reactive textile dye (CI Reactive Red 141) was used as model of colour-causing compound prepared at a concentration of 50 mgl(-1). The best performances of dye removal were obtained with C(2) having a chemical structure comprised of a mixture of polymeric specie (Al45O45(OH)45Cl) and monomeric species (AlCl(OH)2.2H2O and Al(OH)3). The removal efficiency (R(A)) evaluated by measuring the yields of 540 nm-absorbance removal varied from 41 to 96% through 60 min of treatment by imposing a concentration of C2 ranging from 100 to 400 mg l(-1). The effectiveness of the treatment increased and the effluent became more and more transparent while increasing C(2) concentration. The comparison of chemical treatment using C2 coagulant and direct electrocoagulation of CI Reactive Red 141 containing synthetic solution demonstrated the advantage of chemical treatment during the first few minutes of treatment. A yield of 88% of absorbance removal was recorded using C2 coagulant (400 mg l(-1)) over the first 10 min of treatment, compared to 60% measured using direct electrocoagulation while imposing either 10 or 15 V of electrical potential close to the value (12 V) required during C2 production. However, at the end of the treatment (after 60 min of treatment), CI Reactive Red 141 pollutant was completely removed from solution (540 nm-absorbance removal of 100%) using direct electrochemical treatment, compared to 96.4% of absorbance removed while treating dye-containing synthetic solution by means of C2 coagulant.
无论是工业废水还是生活污水，水中的颜色及呈色化合物一直都不受欢迎。此类废水的排放会导致受纳水体中氧气需求过高，因此在排放到生态系统之前需要进行处理。本研究考察了通过化学混凝与直接电凝聚相比，从废水中去除呈色化合物的可能性。所测试的干粉形式的无机混凝剂（C1、C2和C3）分别由S1=[氢氧化钠（7.5×10⁻³M）]、S2=[氯化钠（10⁻²M）]和S3=[氢氧化钠（7.5×10⁻³M）+氯化钠（10⁻²M）]溶液电解制得，使用在12V电势下运行的牺牲铝电极。活性纺织染料（CI活性红141）用作呈色化合物的模型，制备浓度为50mg l⁻¹。使用化学结构由聚合物种（Al45O45(OH)45Cl）和单体物种（AlCl(OH)₂·2.2H₂O和Al(OH)₃）的混合物组成的C2获得了最佳的染料去除性能。通过测量540nm吸光度去除率来评估的去除效率（R(A)），在施加100至400mg l⁻¹的C2浓度下处理60分钟，去除率从41%变化到96%。随着C2浓度的增加，处理效果增强，流出物变得越来越清澈。使用C2混凝剂对含CI活性红141的合成溶液进行化学处理与直接电凝聚的比较表明，在处理的最初几分钟内化学处理具有优势。在处理的前10分钟，使用C2混凝剂（400mg l⁻¹）记录的吸光度去除率为88%，而在施加接近C2制备所需值（12V）的10或15V电势时，直接电凝聚测量的去除率为60%。然而，在处理结束时（处理60分钟后），使用直接电化学处理从溶液中完全去除了CI活性红141污染物（540nm吸光度去除率为100%），而使用C2混凝剂处理含染料的合成溶液时吸光度去除率为96.4%。
