Langmuir 2003, 19, 6851-6856
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Direct Current Magnetic Field and Electromagnetic Field Effects on the pH and Oxidation-Reduction Potential Equilibration Rates of Water. 1. Purified Water Masumi Yamashita,*,† Chris Duffield,‡ and William A. Tiller‡ Department of Geophysics and Department of Materials Science and Engineering, Stanford University, Stanford, California 94305 Received March 24, 2003. In Final Form: April 25, 2003 Effects of low level magnetic and electromagnetic fields (below B ∼ 100 mG for ac magnetic field, and below B ∼ 1000 G for static magnetic field), on purified water that is in the process of equilibration, were investigated. The pH and oxidation-reduction potential (ORP) of distilled and deionized water, previously stored for air equilibration, were measured after exposure to magnetic fields (ac and dc) of different strengths. Readings showed slow and large fluctuations (∼0.05-0.1 pH unit, ∼60 mV for ORP) during the first several hours. These readings looked deceptively stable due to the extreme slowness of the fluctuations. When readings were taken beyond this period, for days, the pH and ORP generally changed slowly toward equilibrium values in a quasi-linear fashion. They changed faster, on average, in those samples that had been exposed to higher magnetic fields. Readings in water samples often “got stuck”, remaining unchanged over an extended period before starting to change again, when stored for equilibration with air and measured in a mu-metal shield, where the ac magnetic flux was ∼0 mG (zero field). These results indicate that, to accurately evaluate the effects of weak magnetic fields on water, subtle experimental conditions such as differential field conditions produced by common lab devices and procedures, and background lab fields, cannot be ignored. Moreover, extending measurements beyond several hours may be essential to reliably observe the presence or absence of these effects.
Introduction It is well-known that water exhibits a wide range of anomalous behaviors with respect to its various material properties.1-4 The literature on the subject is vast and often confusing, covering a variety of spatial size scales as well as temporal response times. The spatial size scales can be conveniently divided into three categories: (1) molecular level properties, including water clusters, with the system considered to be “effective” single phase water and homogeneous on a size scale of 10-7 to 10-6 cm, (2) two-phase or polyphase water properties associated with either classical critical point phenomena or cooperative internal electromagnetic (EM) mode interaction phenomena, with this size scale being treated as an “effective” single phase and homogeneous on a size scale of (stirring alone) > (unstirred, no magnets). The mean pH slope, with this magnet
configuration, was ∼1.6 times larger than that with stirring only. Figure 6 is provided to give a more detailed picture of one set of the raw pH data from which Table 2 was derived. Sample A was stirred with magnets present, while sample B was stirred without magnets. At about the 18 h point, both measurement probes were placed in sample A, and ∼2 h later, both were placed in sample B. This tended to confirm the reliability of the probe measurements. 5. 60 Hz EM Fields versus the H ) 0 Condition. In this set of experiments, the pH was measured both during and after exposure to low intensity ac magnetic fields (“high field” (HF) with B values of ∼40-120 mG, “ambient field” (AF) with B values of ∼3-9 mG, and “zero field” (ZF) with B value of ∼0 mG). Two ac adapters, of the type commonly found in residences and work places, were used as the 60 Hz source, with the field intensity being measured by a triaxial ac magnetic flux meter. In these experiments, the samples were first stored at their field exposure locations for 1-7 days, and then relocated to an area where the magnetic flux was at ambient level (∼3-5 mG), for measurement. For 12 sample pairs of deionized water from the same batch, Table 3 provides ORP slope mean, median, and range values for these 12 sample pairs. One notes that, on average, the ORP evolution rate for AF conditions was about twice that for ZF. Figure 7 provides an example time course for ORP evolution in these two field categories. Note the very long metastable region (between hours 45 and 75) for the ZF case. In the data on aqueous solutions, to be presented in Part 2,13 the HF case provided still higher slopes than the AF case, for comparable evolution times, and appeared to asymptotically move toward zero slope after about 5 days. The temperatures of the water samples in zero field and ambient field shifted in close parallel, so the temperature shift was apparently not the direct cause of the differential behavior of their ORP values. When these water samples were abruptly stirred in the ZF condition compared to the AF condition, there was (13) Mendenhall, W.; Beaver, R. J. Introduction to probability and statistics, 8th ed.; PWS-Kent: Boston, 1991; Chapter 9, pp 322-391. (14) Yamashita, M.; Duffield, C.; Tiller, W. A. DC magnetic field and electromagnetic field effects on the pH and ORP equilibration rates of water; Part II: Aqueous Solutions. In preparation.
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Table 2. pH Slope Variation with Static Magnetic Field and Stirringa exposure condition
mean slope (pH/h)
median slope (pH/h)
slope range (pH/h)
stirred with magnets stirred without magnets standing without magnets
0.0075 (STD ) 0.003) 0.0065 (STD ) 0.003) 0.0037 (STD ) 0.0017)
0.0081 0.0064 0.0038
0.0015-0.012 0.0019-0.011 0.001-0.0065
a Slope is larger with stirring than without (p-value < 0.025). The mean slope stirred with magnet is 1.64 times larger than that with stirring only ((0.94, p-value < 0.10). Distilled water; 10 stirred samples in each condition.
Table 3. ORP Slope Is Greater for Ambient (AF) than Zero (ZF) Magnetic Fielda
a
exposure condition
mean slope (mV/h)
median slope mV/h)
slope range mV/h)
AF ZF ratio
0.16 (STD ) 0.07) 0.076 (STD ) 0.06) 3.75 (STD ) 2.70)
0.16 0.049 3.58
0.07-0.32 0.011-0.17 0.55-7.04
p-value < 0.005. Unstirred deionized water; 12 samples in each condition.
Figure 6. pH of stirred water, with and without magnets. A few minutes before t ) 0, sample A was stirred between two magnets and sample B was stirred without magnets. After linear trends developed, homogeneity of water, and system reliability, were demonstrated by switching probes between samples. (Distilled water.) Meter: Denver150.
Figure 7. Extremely slow ORP equilibration in zero field, compared with ambient field. In zero field, ORP often stabilized at levels where it would not, if in an ambient field. (Deionized water, aged 4 days.) Meter:Denver250.
generally (i) a larger immediate change in pH or ORP level for the ZF compared to the AF, and (ii) a slower transition back to a new, or the same, time-evolution curve for the ZF compared to the AF. This behavior can be readily seen in Figure 8. When one compared two samples from the same batch in the ZF environment with stirring, but either with or without two dc magnets attached to the vessel as in Figure 5, a significantly larger pH and ORP slope always developed for the attached-magnets case. Discussion Several rather remarkable insights concerning water arise from this fairly straightforward and fairly low-tech study. The first is that, even with highly purified water
Figure 8. (a) Larger pH change when stirred in zero field than in ambient field. (Deionized water, stored 2 weeks under typical conditions before stirring, and continued after.) Meter: Denver 250. (b) Large ORP change when stirred in zero field; no change in ambient field. (deionized water.) Meter: Denver 150. (c) New level of ORP, after stirring in zero field, does not persist in this example. (deionized water.) Meter: Denver250.
(approximately ASTM type I, here called deionized water), pH and ORP slopes for samples from the same preparation batch can exhibit a wide range of approximately constant slopes at the ∼20 h monitoring point in the long-term profile. This may relate to H-bond structural differences,
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as distinct from chemical differences, between samples of the same batch. Reviewing the data shows the following spreads of values: (1) The pH slopes for the static water/ no dc magnet experiment samples differed by a factor of ∼80. (2) The pH slope for the stirred water/no dc magnet samples differed by a factor of ∼10. (3) For the static water/ with dc magnet case, the spread was a factor of ∼5. (4) For the stirred water/with dc magnet case, the spread was a factor of ∼8. (5) For the ZF case, the spread was a factor of ∼15. The measurements in Tables 1-3 were made with distilled water and deionized water, over a period of months, during which the quality of the water supply could have varied. Even with the Millipore system, depending on the filter condition, there is inevitable variability of trace elements over time. The remarkable fact that pH and ORP measured in ZF appear to very slowly evolve in a series of quite long-term metastable states, in both the upward and downward directions, points to the presence of appreciable activation barriers for process kinetics that are somehow related to magnetic or EM fields. Perhaps this kind of behavior is related to the morphological nature of the water’s hydrogen-bond structure. If so, the degree of this structure’s rigidity versus malleability may be intimately involved with a proton magnetic resonance-type phenomenon that somehow enhances the flexibility and glissile nature of the H-bond network. Long-time pH and ORP measurements appear to be essential to characterize purified water’s structural state, as distinct from its chemical state. Of course, O2 and CO2 equilibration of the samples with ambient air is typically a fairly slow process but can be speeded up considerably by stirring. This is well understood. What is not so well understood is the enhancement effect associated with the presence of either a dc magnetic field or an ac EM field. Certainly, one expects diamagnetophoresis-type forces to be acting on the water samples via both dc magnetic and ac EM fields. In addition, for ac fields, dielectrophoresis-type and magnetic resonance-type forces are present. Although such forces would enhance the effective diffusion coefficient for various dipolar moieties in the water, the unenhanced diffusion coefficients are sufficiently large (D ∼ 5 × 10-6 cm2 s-1) to allow diffusional mixing over distances of ∼0.1 cm in ∼30 min. This is a time much shorter than the phenomena we are dealing with in these experiments, yet the kinetic enhancement effect increases as the field strength increases. One must also consider changes in ortho/para water15 ratio in the presence of magnetic fields, as such changes are likely to influence both pH and ORP value. (15) Tikhonov, V. I.; Volkov, A. A. Science 2002, 296, 2363.
Yamashita et al.
More than half a century ago, it was shown that the conversion rate between the ortho and para forms of hydrogen in a condensed phase was of second order.16,17 Silvera18 indicated that, for this to occur, simultaneous changes must happen in (a) rotational angular momentum by ∆J ) 1 and (b) triplet and singlet nuclear spin states. He also points to the observation of O2 impurities in H2 as being an extremely effective catalyst of the ortho/para transition to develop a magnetic field-screening sphere of para molecules around each O2 molecule. Ilisca and Paris19,20 have recently provided a new electron-nucleus resonant mechanism to facilitate the ortho/para conversion process. However, at the H and ∇ H values used in this paper, these effects are expected to be small and unlikely to explain the rather large pH effects and ORP effect that we find. On the other hand, if we look at Silvera’s O2 observations in H2, in diamagnetic water, a similar thermodynamic driving force might exist to generate H+ ions via the dissociation reaction of H2O which, in turn, screen the magnetic field of the dissolved O2 species so as to ultimately increase the O2 and perhaps also the CO2 reactions for water in equilibrium with air as H increases. This brings us to the final point that common laboratory electrical equipment, in regular use, provides sufficiently strong fields to stimulate this seemingly anomalous behavior of purified water. The influence of such devices, used by the scientific community in their day-to-day experiments with aqueous solutions and perhaps many other fluids, needs to be more carefully studied and understood. Acknowledgment. This work was partially supported by Ditron, LLC, and the Samueli Institute. The authors wish to thank Professor Norm Sleep and Dr. Walter Dibble, Jr., for helpful guidance during the course of this study, Professor Jim Leckie for the use of his water purification system, and Gravity Probe B for the use of a magnetic shield. Supporting Information Available: Brief description of the procedures developed to enhance the measurement accuracy sufficient for long-term pH and ORP measurements. This material is available free of charge via the Internet at http://pubs.acs.org. LA034506H (16) Motizuki, K.; Nagamiya, T. J. Phys. Soc. Jpn. 1956, 11, 93-104. (17) Peters, G.; Schramm, B. Ber. Bunsen-Ges. Phys. Chem. 1998, 102, 1857-1864. (18) Silvera, I. F. Rev. Mod. Phys. 1980, 52, 393-452. (19) Illisca, E.; Paris, S. Phys. Rev. Lett. 1999, 82, 1788-1791. (20) Paris, S.; Illisca, E. J. Phys. Chem. A 1999, 103, 4964-4968.
